department of materials part ii projects 2013/2014
TRANSCRIPT
DEPARTMENT OF MATERIALS
PART II PROJECTS
2013/2014
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UNDERGRADUATE PART II PROJECTS
The project descriptions can also be found at:
http://www.materials.ox.ac.uk/teaching/part2/pt2newprojects.html
Further projects may be publicised at a later date.
There will be an open afternoon on Tuesday 5 February 2013, with introductory talks
on Part II from the Head of Department and the Part II Co-ordinator. Attendance at
these talks is mandatory for all MS students commencing Part II in Michaelmas Term
2013.
The following staff members can be contacted, from 2.30 – 5.00 pm on the same
afternoon, either in their office or by phone to discuss the projects listed:
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Name Room Building Tel. No.
Dr David Armstrong 15.04 21 Banbury Road 73768
Prof Fernando Audebert 110.20 21 Banbury Road 73731
Dr Hazel Assender 30.06 Hume Rothery Building 73781
Dr Simon Benjamin 195.40 12/13 Parks Road 73732
Dr Paul Bagot 20.09 Hume Rothery Building 73711
Prof Andrew Briggs 195.30 12/13 Parks Road 83336
Dr Jan Czernuszka 110.10 21 Banbury Road 71771
Dr Frank Dillon 317.10 Begbroke 83729
Dr Marina Galano 20.07 21 Banbury Road 73731
Eric Gauger 195.40 12/13 Parks Road 83341
Dr Feliciano Giustino 40.27 Rex Richards Building 12790
Prof Nicole Grobert 30.13 Holder Building 73672
Prof Chris Grovenor 30.17 Hume Rothery Building 73737
Dr Colin Johnston Begbroke 83705
Dr Antal Koos 317.10 Begbroke 83729
Dr Edward Laird Will discuss projects on 7 Feb. +31 64128749
Dr Kanad Mallik 40.03 Engineering & Techology Bldg. 83097
Prof. James Marrow 110.10 21 Banbury Road 73938
Laura Miranda-Perez 317.10 Begbroke 83729
Dr Michael Moody 179.30 Hume Rothery Building 73693
Prof Peter Nellist 154.30 Holder Building 73656
Dr Rebecca Nicholls 30.23 Holder Building 73707
Dr Keyna O’Reilly 10.02 21 Banbury Road 73743
Dr. Kyriakos Porfyrakis 30.12 12/13 Parks Road 73724
Prof. Steve Roberts 10.16 21 Banbury Road 73775
Dr Jason Smith 30.10 12/13 Parks Road 73780
Dr Susie Speller 20.05 21 Banbury Road 73734
Dr Kumar Sundaram 110.08 21 Banbury Road 73778
Dr Ed Tarleton 110.15 21 Banbury Road 73768
Prof Richard Todd 40.23 Engineering & Techology Bldg. 73718
Dr Jamie Warner 20.03 12/13 Parks Road 73790
Prof Angus Wilkinson 10.19 21 Banbury Road 73792
Dr Peter Wilshaw 50.15 Engineering & Techology Bldg. 73736
Dr Jonathan Yates 40.17 Rex Richards Building 12797
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Dr Robin Young 10.02A Begbroke 83723
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Fundamentals of Creep in ODS Steels
David Armstrong/Angus Wilkinson
Oxide dispersion strengthened (ODS) steels are regarded as critical materials for
high temperature applications in future advanced nuclear fission and fusion reactors,
where they will be subjected to high levels of neutron irradiation damage. While
much work has been carried out assessing the static mechanical properties of these
materials in both the irradiated and unirradiated conditions there is little data on the
creep performance of these materials after irradiation, and how specific
microstructural features control the creep mechanisms. In this project Ion irradiation
will be used to mimic neutron damage and then nanoindentation used to measure
creep parameters in both irradiated and unirradiated materials. The deformation
structures will then be studied using SEM and EBSD.
Characterization of gas-barrier polymer films
Hazel Assender
The wider exploitation of polymer electronics e.g. PV, or flexible displays, is limited
by the performance of transparent flexible gas barrier materials to exclude water
vapour from the sensitive device materials. The part II project will be focused on
characterization of what limits the performance of the best films by use of the ‘Ca
test method’ by observing the microstructure of the features that develop as a thin
layer of Ca reacts with water vapour which passes through micro- and nano-scale
holes in the barrier material.
Polymer surface crystallization
Hazel Assender
We have demonstrated that in the more-mobile surface region of a polymer, it is
possible to induce surface-specific crystallization by annealing at temperatures
slightly below the bulk crystallization temperature. Thin-film crystallization has
previously been reported in the literature in a number of polymers, and this project
will seek to revisit these materials to demonstrate whether the particular
morphologies observed previously are associated with crystallization of this more-
mobile surface region.
Humidity and temperature sensors using low-cost manufacturing methods
Hazel Assender
Simple electronic devices are now being developed based on organic materials that
can be deposited using roll-to-roll (R2R) manufacture, allowing for large numbers to
be produced very cheaply. The project seeks to exploit some materials’ sensitivity to
moisture and temperature to build simple sensor devices suitable for R2R
processing that might be incorporated, for example, into packaging.
Atomic-scale Characterization of Catalytic Alloys
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Paul Bagot/Michael Moody
Catalysts in fuel-cells/automobile exhausts rely on expensive metals including Pt,
Rh, Ru and Pd. The surface structure and composition of these alloys can alter
markedly under high temperature operation, which is still not fully understood. This
project will use Field Ion Microscopy (FIM) and Atom Probe Tomography (APT) to
investigate structural/chemical changes to catalyst alloys following exposure to
realistic operating environments. The student will also be involved in cutting-edge
developments to look at individual catalyst nanoparticles (in collaboration with Univ.
Bath).
High-temperature oxidation of Nickel-superalloys
Paul Bagot/Michael Moody
Nickel-based superalloys operate in extreme environments such as gas turbines for
aerospace/power generation and in racing automobile exhausts. The oxidation
behaviour of these alloys is complex, and understanding this is the key to pushing
them to operate at higher temperatures for future high-efficiency engines. This
project will use Atom Probe Tomography (APT) and complementary electron
microscopy (SEM/TEM/EDX) to characterize the kinetics of early-stage oxidation and
identify possible failure sites in a series of nickel-superalloys.
Energy transfer and distribution in quantum nanostructures
Simon Benjamin/Erik Gauger
Energy transfer through molecular networks occurs as an early step in the process of
photosynthesis. Efficient energy transfer and distribution will also play a crucial role
for next generations technologies ranging from light harvesting to molecular
electronics and devices. However, the physical mechanisms underlying this process
are not yet properly understood. This project is concerned with developing suitable
techniques for investigating energy transfer in quantum nanostructures.
This project would be suitable for a student with exceptional mathematical talent and
/ or an interest in developing code for large parallel computer clusters.
Spatially controlled self expanding tissue expanders
Jan Czernuszka
Hydrogel systems have been developed that can expand uniaxially. The swelling
ratio and direction of swelling can be controlled via thermo-mechanical treatments.
The aim of this project is to manufacture a device with different expansion properties
within the same device. The work will involve materials processing, mechanical
testing and characterisation of these polymer hydrogel based systems
Scaffolds for neurons
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Jan Czernuszka
As part of a collaborative project with colleagues in DPAG we are developing
scaffolds to help tissue engineer neuronal networks. The ultimate aim is to repair
neurodegenerative diseases. The project will involve processing of scaffolds based
on GAGs and PGs. This is a new area for tissue engineering
An injectable bone augmentation system
Jan Czernuszka
Bone is second only to blood in the needs of surgeons. This project will develop an
injectable system based on ECMs and calcium phosphates as a delivery vehicle for
orthobiologics. The initial rheology and how this varies with time in the body is
important as is the release profile of the eluting components. The project will also
involve extensive characterisation of the system using SEM, XRD, FTIR and DSC.
Development of aluminium matrix nanocomposites
Marina Galano/Fernando Audebert
This project is based on the development of novel Aluminium Matrix Complex
Nanocomposites with combinations of reinforcement strategies at the nanoscale that
offer unique properties to target specific applications with an enhancement of
combined properties e.g. increase thermal stability, ductility, strength and Young’s
modulus. New materials will be used as nanoreinforcements or plasticizers for
improving targeted properties
A detailed study on the processing and the mechanisms responsible for
microstructural stability and mechanical properties is required to develop these new
Al matrix complex nanocomposites and to provide a platform of knowledge for
designing the right material for each application.
Materials will be manufactured by a powder metallurgy route and microstructural and
mechanical properties characterization will be carried out.
Manufacturing and characterization of new light weight alloys
Marina Galano/Fernando Audebert
The design of new light weight materials (Al and Mg based) is of extreme importance
to industry due to the constant need to develop materials that combine high strength
and light weight.
This project is going to be based on the development of new alloys systems by
means of diverse rapid solidification techniques. These rapid solidification
techniques allow obtaining microstructures that combine several stable and
metastable phases such as amorphous, quasicrystalline and crystalline phases.
Materials are going to be characterised by X- Ray analysis, calorimetry and electron
microscopy techniques. The evolution of the microstructure is going to be studied by
means of heat treatments, structural characterisation and microhardness in order to
understand the phase transformations
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Atomic-scale computational design of two-dimensional transition-metal
chalcogenide nano-superlattices
Feliciano Giustino
In the very same scientific work that initiated graphene research [KS Novoselov et al,
PNAS 102, 10451 (2005)] it was shown that it is possible to produce many two-
dimensional atomic crystals by mechanical exfoliation, for example MoS2, NbSe and
BN. While during the first few years of graphene research the attention was focused
entirely on graphene and its modifications, more recently the attention has been
shifting towards other promising 2D crystals. For example last year the the first
transistor with a monolayer-thick MoS2 channel was reported [B. Radisavljevic et al,
Nature Nanotech. 6, 147 (2011)]. The next step in the world of 2D electronics and
photonics is to ask what would happen if we could combine together different 2D
crystals in various nanoscale stacking arrangements. For example by stacking
metallic and insulating nanosheets [S. J. Haigh et al, Nature Mater. 11, 764 (2012)] it
could be possible to form nanoscale Schottcky contacts for photovoltaics or sensing.
In this project we will proceed to explore the electronic and optical properties of
various combinations of transition-metal chalcogenide nano-superlattices using
density-functional theory calculations. We will investigate how band structures,
effective masses, and optical absorption are modified when 2D crystals of transition
metal chalcogenides (TMC) are stacked in various arrangements. The goal of this
project is to identify design rules for TMC nano-superlattices using atomic-scale
computational design. This project requires a good understanding of quantum
mechanics and solid state physics, willingness to learn Unix shell scripting and some
Fortran programming, and will involve the use of the high-performance computing
clusters in the MML.
Graphene and boron nitride lateral heterostructures
Antal Koos/Nicole Grobert
Recent advances in CVD methods have enabled the production of graphene and
hexagonal boron nitride, but controlled fabrication of heterostructures in these
systems has not been achieved. Graphene/h-BN interfaces are of particular interest,
because areas of different atomic compositions may coexist and the bandgap can be
engineered. The aim of the project is to develop a CVD process that allows for the
spatially controlled synthesis of lateral junctions between electrically conductive
graphene and insulating h-BN. It is envisaged to publish the findings in a peer
reviewed journal and conference participation will be encouraged.
Fast and facile synthesis of nanoparticles with dedicated functionalities
Frank Dillon/Nicole Grobert
The synthesis of monodisperse nanoparticles of transition metal oxides is of great
interest since they display an extensive assortment of structures, properties, and
phenomena. A multitude of procedures have been developed for their synthesis,
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unfortunately most are relatively expensive and time consuming. Recently, new
techniques for the precise structural control of these nanoparticles were developed in
house. The aim of this project is to synthesise and characterise a range of transition
metal /metal oxide nanoparticles using this fast and inexpensive method. The shape
and size of the particles will be systematically varied to determine their effect on
functionality. It is expected that the findings will be published in a peer reviewed
journal and conference participation will be encouraged. It is envisaged to publish
the findings in a peer reviewed journal and conference participation will be
encouraged.
Novel catalysts for the growth of coiled carbon nanotubes
Frank Dillon/Nicole Grobert
The unique 3D structure and resultant properties of coiled carbon nanotubes (CCNT)
have led many researchers to consider their use for various applications ranging
from ‘nano-springs’ to novel reinforcements for composites. However, the synthesis
of CCNTs in high yield with control over coil morphology remains a massive
challenge. The aim of this project is to investigate various chemical vapour
deposition synthesis routes for CCNT. The effect of temperature, time and gas
mixtures on the morphology, yield and purity of the CCNTs produced will be
revealed. It is envisaged to publish the findings in a peer reviewed journal and
conference participation will be encouraged.
Ultra strong and ultra light carbon nanotube inorganic composite materials
Richard Todd/Laura Miranda/Nicole Grobert
In recent years, carbon nanotubes (CNTs) have been heralded as the ultimate
reinforcement material for ultra strong and ultra light organic and inorganic
composite materials. However, research on CNT composites has been hindered by
the fact that commercially available CNTs are often tightly agglomerated and hence
require sophisticated dispersion techniques to detangle them before they can be
employed as fillers or reinforcements. Recent developments in the production and up
scaling of nanotubes in Oxford have paved the way towards the successful
exploitation of CNT properties for the generation of multifunctional CNT composite
materials. This project will be part of a larger research activity and will produce and
characterise novel inorganic composites using various types of in-house generated
CNTs to move further towards materials with genuinely outstanding properties. It is
envisaged to publish the findings in a peer reviewed journal and conference
participation will be encouraged.
Novel routes to manufacturing layered inorganic nanomaterials
Frank Dillon/Nicole Grobert
Carbon nanotubes, have attracted increasingly more attention due to their
outstanding properties in recent years. Concurrently, other 1D nanomaterials such
as, inorganic nanowires and nanotubes of other layered materials, such as MoS2,
WS2, BN, have been explored. Recently, new techniques for the precise structural
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control of WS2 nanomaterials were developed in house. Larger laboratory scale
production, however, is still scarce and needs to be developed in order to make
these novel nanomaterials viable for further characterisation, manipulation and
application. This project will be focusing on the development of novel routes to
inorganic 1D nanomaterials using chemical vapour deposition techniques. In this
project the student will work closely with other members of the group and the
samples produced by the student will be an integral part of a collaborative project
with Dr Michael B Johnston (Department of Physics) and Dr Kylie Vincent
(Department of Chemistry). It is envisaged to publish the findings in a peer reviewed
journal and conference participation will be encouraged.
NanoAg bonding
Colin Johnston
Increasingly electronics are being required to operate at higher temperatures where
conventional interconnect technologies fail. In recent years nanoparticulate silver
has been demonstrated as a candidate for joining electronic components. The
nanosized material “melts” or sinters at relatively low temperature but has a high
reflow temperature. The exact mechanisms involved in this sintering are poorly
understood. This project will explore the processing space and use high
temperature microscopic imaging to investigate the sintering process.
Tin whisker formation
Colin Johnston
Lead free solders, usually based around high tin alloys are now the dominant solder
material. However, under certain conditions, for example under mechanical strain or
in high temperature variations, tin whiskers can grow and cause electrical shorts.
This project will investigate tin whisker formation as a function of mechanical strain
and temperature with in situ microscopic imaging to better understand the growth
mechanisms and propose methods for mitigation.
Carbon nanotube fabrication for quantum devices
Edward Laird / Andrew Briggs
Carbon nanotubes are attractive materials for electronic devices, especially quantum
computers, but a central challenge is avoiding contamination during fabrication. You
will develop the new technology of stamping, in which a single pristine nanotube is
placed over a prefabricated device. The goal is devices in which the same nanotube
can be measured both electrically and through TEM imaging. This will involve
training in nanofabrication, electron microscopy, and low-temperature
measurements.
Three-Dimensional Studies of Damage by X-ray Tomography
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James Marrow
We will study the development of damage (yielding and crack initiation) in
engineering materials, such as ceramic matrix composites, metal matrix composites,
ODS steels, nuclear graphite and concrete, mapping displacements and strains in
3D by digital image correlation of high-resolution X-ray computed tomography data.
We aim to understand the effect of microstructure on criteria for deformation and
failure initiation. This is in support of international collaborations on Generation IV
nuclear fission materials.
Effects of multi-axial loading on short crack propagation in engineering
materials
James Marrow
We will study the propagation of small crack-like defects in 3D, under displacement
controlled uniaxial flexure (3-point bend) and equi-biaxial flexure (ball-on-ball
loading). Displacements around the crack front in model and engineering materials,
under different levels of constraint by multi-axial loading, will be studied at high
resolution using techniques including X-ray tomography and image correlation. This
supports the development of miniature specimens to study the effects of extreme
environments on nuclear materials.
Novel techniques to measure strain-hardening in nuclear materials by nano--
indentation testing and 3D modelling
James Marrow
Ion-irradiation may simulate neutron irradiation in advanced nuclear fission and
fusion materials, but the irradiated volumes are too small to obtain strain hardening
behaviour by experiment. X-ray computed nano-tomography, combined with image
correlation, measures the plastic zone under nano-indents in ODS steels, and may
be applied to irradiated samples, tested at elevated temperatures. Via experiments
on ODS steel and model materials, you will develop finite element modelling
methods to extract the strain hardening properties.
Atom Probe Investigation of Thermal Ageing on the Microstructure and
Properties of 17-4 PH Steel
Michael Moody/Paul Bagot
17-4 PH steels are used for structural components in aerospace and nuclear reactor
applications. Unfortunately, during service, properties can change. At elevated
temperatures, additional copper precipitation can occur and the ferrite can undergo a
spinodal decomposition to α and chromium-rich α’ (sometimes called 475 °C
embrittlement). These changes increase strength and hardness at the expense of
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embrittling the steel. Such changes are time and temperature dependent and can
also be accelerated by fast neutron fluxes in nuclear applications.
The project will carry out series of precipitation hardening treatments, at different
times and temperatures, on solution annealed material. The 3D atom-by-atom
analyses provided by atom probe tomography will further understanding of the
effects of copper precipitate size and number density on mechanical properties. A
selected sub-set will then be thermally aged to determine the in-service changes and
their interaction with the original microstructure. A model will be developed to predict
mechanical properties. The project will be undertaken in collaboration with Rolls
Royce.
Detection of single energetic ion tracks by photoresist polymers and AFM
imaging
S Myhra/N Falzone/Chris Grovenor
A joint project undertaken by a group at the Churchill Hospital and the Department of
Materials has been exploring a novel method for the detection of single energetic ion
tracks for possible applications in fields ranging from archeometry to targeted cancer
therapy with radioactive drugs. Preliminary results from a related project obtained in
a previous Part II (G. Royle, 2012) were promising in terms of the sensitivity and
spatial resolution of the technique. This follow-on project will develop a better
understanding of the physics and chemistry of the interactions of energetic ions with
photoresist polymers and biological materials.
Electron microscopy characterisation of nanoparticle composition or
morphology changes in catalyst materials
Pete Nellist (co-supervised by Dr Dogan Ozkaya of Johnson-Matthey)
Many heterogeneous catalyst systems (such as those used in automotive exhausts
or hydrogen fuel cells) consist of metal nanoparticles on carbon or oxide supports.
Often, these nanoparticles can change composition or morphology during use. The
aim of this project is to use quantitative electron microscope techniques at nanoscale
spatial resolution to make quantitative measurements of these changes. This project
will involve both experiments using the electron microscopes in the department along
with sophisticated data processing methods.
Modelling of 2D nanomaterials
Rebecca Nicholls/Jonathan Yates
Two dimensional inorganic materials (eg MoS2, WS2) are of great interest due to
their potential applications in areas such as nanoelectronics. The controlled
introduction of defects into these materials enables control of their electronic
properties; an essential step towards the realization of practical devices. This project
will use quantum mechanical simulations and high-performance computing to model
these materials with the aim of guiding on-going experimental work in the
department.
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Nucleation and growth of intermetallic phases in Al alloys
Keyna O’Reilly/Kumar Sundaram
Intermetallic phases such as Al-Fe compounds and Al-Fe-Si compounds form in all
Al alloys and have a significant effect on the mechanical properties and
processability of the alloys. Historically the morphology of these intermetallics has
been studied using conventional metallography which only presents a 2D slice
through the material. More recently, we have been investigating the 3D structure of
these intermetallics by dissolving away all of the Al matrix and collecting the resulting
intermetallics for viewing in the SEM. So far we have revealed the morphologies of
intermetllics in 1xxx series and 6xxx series alloys, and they are vastly different from
one another. 6xxx series alloys have a highly connected 3D structure containing
complex morphologies, whereas 1xxx series alloys typically contain spherical
clusters and needles. This project will investigate the morphologies found in other
industrially relevant Al alloys and determine what it is about the nucleation and
growth mechanisms operating which is determining which structure forms.
Functional intermetallic particles?
Keyna O’Reilly/Kumar Sundaram
Intermetallic phases such as Al-Fe compounds and Al-Fe-Si compounds form in all
Al alloys. We now have the ability to dissolve away the Al matrix of the alloy and to
collect these intermetallics. The intermetallics can have different morphologies,
including fine-scale spherical clusters and needles. In other materials and chemical
systems it has been shown that many nano-particles have special properties. This
project will investigate whether intermetallics formed in Al alloys could be used to
provide specialist functionality. Additions of transition elements such as V and Mo
have been seen to influence the morphology of the intermetallics, and this may well
be true of other transition elements. This project will use a combination of additions
of transition metals and the use of rapid solidification to produce very fine scale
intermetallics which will then be extracted from the matrix and their functionality
investigated.
Control of iron rich intermetallics (dross): nucleation and growth during hot
dip galvanizing of steel sheet
Keyna O’Reilly/Kumar SundaramA number of different galvanic coatings can be applied to sheet steel by hot dipping.
The 55Al-Zn coating has two principal phases in its microstructure. One phase is the
primary aluminium-rich dendritic phase that begins to grow initially during
solidification. The other is an inter-dendritic zinc-rich region that forms when the zinc
concentration in the solidifying liquid reaches a higher level. . Other phases in the
microstructure of the coating layer include small discrete particles of elemental
silicon, and an iron-rich phase which results because the coating bath becomes
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saturated with iron during the production process. Saturation of iron in the bath
results in the precipitation of a dross in the liquid metal. The dross gradually sinks
and deposits at the bottom of the bath. Once a significant amount of bottom dross is
accumulated, turbulence can dislodge particles of the accumulated dross and bring it
into contact with the steel strip causing quality and maintenance issues. A new
method has been proposed for the removal of the dross by introducing a
recirculatory loop in the process which continuously cycles a proportion of the molten
zinc through a treatment cell to remove the dross. This project will investigate
processes which could be employed within the treatment cell for the effective
removal of dross.
In collaboration with N-Tec and of interest to Bluescope Steel, Corus and Wheeling
Nisshin.
Molecular Machines with Fullerene Derivatives
Kyriakos Porfyrakis
The project involves the synthesis of fullerene derivatives that will have specific
functionality. Well known reaction methods will be used to anchor functional groups
on the fullerene cage. The functionalized fullerenes could be used as a thread and
axle component for potential anion templated rotaxane synthesis. For this reason,
we will collaborate with the group of Prof. P.D. Beer in the Chemistry Department,
who has vast expertise in the synthesis of interlocked molecular architectures.
Synthesis of N@C60 Derivatives for Quantum information Processing
Kyriakos Porfyrakis
N@C60 is a remarkable molecule with the longest electron spin coherence time (T2)
ever recorded for a molecular system. In order to use this molecule as a qubit for a
quantum computer, it is necessary to be able to create building blocks with multi-
qubit arrays. As a first step, the project involves the synthesis and purification of
N@C60. The second step involves the chemical modification of this endohedral
fullerene in a way that gives it functionality for the development of dimer and
oligomer molecules.
Synthesis of Fullerene-based, Donor-Acceptor Dyads
Kyriakos Porfyrakis
Fullerenes have excellent electron affinity and are frequently used as electron
acceptors in donor-acceptor linked systems (dyads). The project involves the
chemical synthesis of dyads made of fullerenes and donor molecules such as
porphyrins. The formed dyads are expected to have long-lived charge separated
state with high quantum efficiency. The dyads will be characterized by mass-
spectrometry, UV-Vis-NIR, FTIR and ESR spectroscopies. Such systems are
attractive for solar-energy conversion systems.
Master Thesis/Diplomarbeit
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Structural characterization in Cr/Cu (or Cu/W or Ti/W) nanocomposite prepared
by high pressure torsion (HPT) using advanced TEM techniques
Steve Roberts
Immiscible binary system, such Cu/Cr and Cu/W, can be transformed to
nanocomposites and become partly miscible by sever plastic deformation.
In this project, nanocomposites will be produced by HPT method. Mechanical
properties, such as hardness and tensile strength, will be measured. The nano-
structure of these nanocomposites will be intensively characterized using TEM,
HRTEM and analytical TEM. The majority of work in this project will be chemical
composition measurement using energy dispersive X-ray spectroscopy (EDXS) or
electron energy loss spectroscopy (EELS) techniques in order to get chemistry
profile across the grain boundary by quantifying the numerous EELS and EDXS
spectrum-images. The goal is to understand better the development of
supersaturated solid solutions during plastic deformation. Ensuing structural study
will be achieved by HRTEM and TEM. The overview morphology of nanocomposite
will be also studied by SEM.
Supervisors:
Dr. Zaoli Zhang Prof. Reinhard Pippan
Erich Schmid Institute of Materials
Science
Austrian Academy of Sciences
Erich Schmid Institute of Materials
Science
Austrian Academy of Sciences
Institute of Material Physics, Univ. Leoben
Jahnstraße 12 Jahnstraße 12
8700 Leoben 8700 Leoben
Austria Austria
Tel: +43 3842 804 311 Tel: +43 3842 804 308
E-mail: [email protected] E-mail: [email protected]
Master Thesis/Diplomarbeit
Temperature effects on the mechanical behavior of thin films on flexible
substrates
Steve Roberts
To advance the flexible electronic technology understanding, the research of thin film
systems like metal films on polymer substrates is very important. The main goal is to
assess the mechanical behavior in order to predict the lifetime of such materials
depending on applied load, film thickness and also the operating temperatures. In
this study, as-deposited copper films on polymer substrates will be examined at
elevated temperatures. Films of different thickness (50-500nm) will be strained at
two difference temperatures (150°C and 350°C) to determine the influence of the
temperature, film thickness and substrate on the fracture and deformation behavior
as measured with the localized deformation spacing. At these temperatures, Cu may
have enough energy to cause grain growth or stress induced grain growth with
straining and thus will also be evaluated. With increasing film thickness, the localized
deformation increases and the probability of film delamination decreases. This
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behavior is due to the influence of the interface structure which becomes dominant
as the film thickness decreases. Comparison of the films strained at elevated
temperatures to room temperatures will be made and the role of temperature,
thickness, and grain size determined.
Supervisor Leoben:M.J. Cordill Reinhard Pippan
Erich Schmid Institute of Materials ScienceAustrian Academy of Sciences
Erich Schmid Institute of MaterialsScienceAustrian Academy of SciencesInstitute of Material Physics, Univ.Leoben
Jahnstraße 12 Jahnstraße 12
8700 Leoben 8700 Leoben
Austria Austria
Tel: +43 3842 804 311 Tel: +43 3842 804 308
[email protected]:[email protected]
Details: High Temperature experiments – Cu/PI
a) 50, 100, 200, 500 nm Cu on PI
b) Characterize unstrained & strained films: SEM, EBSD, AFM, TEM?
c) Strain films (and bare substrates) at 150°C and 350°C with Zwick (with
vacuum and lead cell)
d) Measure deformation spacing using necks and cracks, thickness, t
temperatures effects, and the role of grain size on deformation
e) TEM cross-sections - change in interface structure (with MJC and ZZ?).
Properties of irradiated Silicon Carbide
David Armstrong/Richard Todd/Steve Roberts
Silicon carbide has been identified as a key material for high temperature
applications in both advanced fission and fusion power plants. However in these
applications the SiC will undergo significant microstructural and chemical changes
due to neutron irradiation. In particular the transmutation of carbon into helium could
result in He levels of up to 10,000appm/year.
This project will use heavy ion and helium ion implantation (at the National Ion beam
Centre, University of Surrey ) to mimic radiation damage in SiC. This produces an
implanted layer on the order of 3µm thick and to study its mechanical properties
nanoindentation, SEM, AFM and Raman microscopy will be used. The changes in
mechanical properties will be related back to microstructure and damage level to
gain a better understanding of the influences of neutron damage and helium
production on the mechanical properties of SiC.:
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Modelling Micromechanics of irradiated materials
Ed Tarleton/Steve Roberts
Small-scale mechanical testing techniques are currently being developed and used
in Oxford and elsewhere for the study of thin ion-irradiated layers (ion irradiation is
an analogue for neutron damage as produced in fusion and fission reactors). This
project will involve modelling micro-pillar tests on irradiated materials conducted by
researchers in Oxford.
The student will first learn the principles of dislocation modelling and finite element
analysis before learning how to run simulations, using a coupled 2D discrete
dislocation dynamics + finite element code, already developed in Matlab. Simulations
for different specimen sizes and different material properties will be set up and the
results will be compared with the experimental load-displacement curves. There may
also be the opportunity to develop the model further to include effects such as
dislocation pinning at obstacles.
The results will give a deeper understanding of micron-scale plasticity and should
show the possibilities and limits of 2-D DDD simulations for studying such problems.
The student will gain knowledge of two different modelling techniques (dislocation
dynamics and FEM) as well as learning how to use Matlab.
Optical and magnetic characterisation of colour centres in diamond
Jason Smith
Diamond and its crystal defects provide an extremely attractive platform for a variety
of applications, from biosensing and nano-magnetometry to quantum information
processing. Despite enormous progress in recent years in the synthesis of diamond,
many of the defects observed have yet to be well characterised. In particular the
negatively charged nitrogen-vacancy centre (NV-) remains the only defect that is
known to possess optical transitions that are sensitive to the spin state of the
electrons in the defect, key to a number of advanced applications. This project will
involve the optical and spin resonance characterisation of defects in diamond, and
the application of these defects to nano-scale magnetic field sensing. You will be
trained in a range of spectroscopic techniques and will be part of a small but
dynamic team working on this topic. The project will involve communication with
industrial collaborators including DeBeers and Element Six Ltd.
Spectroscopy of light harvesting molecules using resonant optical
microcavities
Jason Smith
This project will involve the optical spectroscopy of photosynthetic molecules as a
means to understanding in detail the multi-stage energy transfer processes that are
crucial to their effectiveness as light harvesters. You will use a range of
spectroscopic methods for this study, including novel techniques being developed in
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the group in which the molecules are placed in resonant optical microcavities that
modify their fluorescent properties. The project is part of a larger research project
being carried out in collaboration with Prof Robert Taylor in the Department of
Physics, funded by the Martin School Oxford.
Semiconductor Nanocrystal lasers
Jason Smith
Semiconductor nanocrystal quantum dots offer potential for development of printable
optical gain media that can be used in optical amplifiers and lasers, but there are
several outstanding challenges to be addressed. This project will involve fabricating
devices that allow lasing experiments to be performed in a controlled way, and using
them to establish information that will feed into the design of improved materials. You
will be trained in a range of optical spectroscopy techniques, and will work in a small
team within the group focused on this topic, and which interfaces with both academic
and industrial collaborators regarding the design and synthesis of materials. The
project is supported by Samsung Electronics.
Microstructural characterisation of high temperature superconducting bulk
materials
Susie Speller
The (RE)BCO (RE = Y, Nd, Sm, Gd, etc.) family of bulk, melt processed high
temperature superconductors (HTS) is the subject of extensive world-wide
developmental research because the very high magnetic fields that can be trapped
in these materials make them suitable for a wide range of applications
(http://www.youtube.com/watch?v=heauu4Um5b4). This project will use EBSD and
EDX analysis to investigate the microstructure of state-of-the-art melt processed
bulks produced by Prof. David Cardwell’s group (Cambridge University Engineering
Dept).
Investigation of phase separation phenomena in novel superconductor and
topological insulator single crystals
Susie Speller
Single crystal samples are typically used to investigate the magnetic and electronic
properties of novel device materials. This project involves using SEM/EDX and AFM
to develop a better understanding of the phase separation phenomena that influence
their properties. The materials studied will include Fe-based superconductors and
topological insulators, both of which are considered to be “hot topics” in condensed
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matter physics. Samples will be grown by collaborators in the Physics Department
and at PSI*.
*Paul Scherrer Institute, Switzerland.
Flash sintering of ceramics
Richard Todd/Peter Wilshaw/T. Rodriguez Suarez
Normally, it takes several hours at a temperature well in excess of 1000 C to sinter a
structural ceramic. However, it has recently been discovered that ceramics can be
sintered in a few seconds with furnace temperatures below 1000C by applying a
voltage to the specimen whilst it is heated. We have repeated the result and it seems
to occur due to a thermal runaway effect in which the current and specimen
temperature rapidly increase within a few seconds, also causing the specimen to
sinter. The aim is to answer some of the many questions that have arisen concerning
the science and practical use of this new phenomenon.
Synthetic Graphene for Electronic Applications
Jamie Warner
The 2D crystalline nature of graphene makes it suitable for large area transparent
conducting electrodes and in nanoelectronics. The biggest challenge in synthetic
graphene is achieving large single crystals of graphene and uniformity in the layer
number on the centimeter scale. We have recently shown how chemical vapour
deposition (CVD) can be used to grow centimeter scale continuous films of pure
monolayer graphene with graphene crystal grain sizes approaching the millimeter
scale. This project will extend this body of work to focus on understanding the growth
mechanisms behind CVD grown graphene and then developing approaches to
improve the atomic structure and electronic properties. Techniques to transfer the
sheets to transparent substrates, such as glass or flexible polymers will be examined
and the sheet resistance determined. Nanoelectronic devices such as field effect
transistors and Hall bar structures will be fabricated using lithography in order to
evaluate the electronic properties of the synthetic graphene. The material produced
in this project will underpin a wide range of applications based on graphene and has
the potential for significant impact.
Sensor Technology Based on Large Area Synthetic Graphene
Jamie Warner
Sensor technology, such as touch screen displays and pressure/strain sensors, will
be developed using graphene. The graphene will be synthetic and of large area,
produced using metal catalyst assisted chemical vapour deposition. Processing
methods for transferring the graphene onto transparent flexible polymer substrates
will be developed. This project aims at bringing graphene into application and will
utilize recent advances within the group for producing outstanding synthetic
graphene material. Optical and electron beam lithography will be used to pattern the
graphene and metal electrodes for devices. Interfacing with computer hardware will
be undertaken to achieve functioning sensor technology.
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Graphene-nanocrystal solar cells (Jamie Warner and Andrew Watt)
Jamie Warner/Andrew Watt
Utilizing graphene in opto-electronic devices will require the effective integration of
other nanomaterials to produce hybrid nanosystems. Inorganic nanocrystals such as
PbS, ZnSe, TiO2 and Si, have unique semiconducting properties with band gaps that
span from the near-IR to UV. This project will focus on synthesizing novel inorganic
nanocrystals using solution-phase chemistry. Control over the shape to tailor
spherical, rod and branched structures will be investigated. Variation of surface state
morphology will be conducted through various chemical approaches to control the
inter-nanocrystal interactions. Synthetic graphene will be produced using chemical
vapour deposition. Composite hybrid devices will be fabricated that use synthetic
graphene as a working transparent conducting electrode and the inorganic
nanocrystal as the active functional nanomaterial. Viability in solar cells will be
explored.
Effects of dilute alloying on the types and properties of grain boundaries in
copper
David Armstrong/Angus Wilkinson,
During the course of our work on grain boundary embrittlement of Cu by small
Bi(0.02wt%) additions we have noted that coherent twin boundaries are almost
entirely suppressed in the cast alloy even though they are low energy and prevalent
in pure Cu. The effects on mechanical properties are similarly profound. This
project will explore the extent to which other low melting point, low symmetry metallic
alloying additions (eg Sb, Sn, In, Ga) affect the statistics of grain boundary types and
properties in Cu. These will be studied by a combination of bend testing,
nanoindentation and EBSD.
[Micro-mechanical measurements of fracture toughness of bismuth embrittled copper
grain boundaries, DEJ Armstrong, AJ Wilkinson, and SG Roberts, Philosophical
Magazine Letters, (2011) vol. 91, 394-400]
What does Peening Really do?
Angus Wilkinson
Peening introduces a surface layer of highly deformed material and used in many
industries as a means of inhibiting crack formation though fatigue, fretting, and/or
stress corrosion. The deformation process is known to introduce residual stresses
that are on the average compressive near the surface, and work hardens the metal
to increase flow stress. This project will study peened Ti-alloy and use
nanoindentation to assess near surface hardening, and high resolution EBSD
mapping to assess dislocation content and local stress variations at the sub-grain
level. The project will involve interaction with Rolls-Royce.
Template Matching – Delivering a Step Change in EBSD Analysis
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Angus Wilkinson/Ben Britton*
Automated analysis of electron backscatter diffraction (EBSD) patterns for crystal
phase and orientation has remained largely unchanged over the last two decades (ie
your lifetime!). This project will develop a new approach based upon template
matching, where experimental patterns are compared to a library of simulated
patterns, which represent potential phases and crystal orientations present in the
sample. Pattern simulation code is available and the project will centre on developing
the automated image analysis procedures needed to make reliable, rapid and
quantitative identification of the simulation that best fits the observed pattern. We will
look at important materials systems which conventional EBSD struggles to correctly
analyse due to small (few percent) tetragonal distortions from cubic symmetry (eg
martensite, barium titanate - piezoelectric, Cu(In,Ga)Se2 –solar cells, Fe-based
superconductors)
(* Imperial College London)
Passivation of semiconductor surfaces for high efficiency solar cells
Peter Wilshaw
Carrier recombination at surfaces and interfaces in solar cells reduces their
efficiency. For future generations of high efficiency solar cells it is essential that
cheap techniques are found for producing semiconductor/dielectric interfaces with
very low recombination. There are two possible elements to this project. The first is
to apply techniques we have already successfully developed for high quality thermal
oxide to cheaper oxides more suitable for use in solar cells (plasma enhanced
chemical vapour deposition oxide!). The aim will be to determine the optimum
processing conditions and the long term stability of the effect. This process is called
passivation. The student performing the work will be involved in deposition of the
dielectrics using semiconductor facilities, characterisation of their properties using
sophisticated electronic techniques and then modification by charge deposition and
further testing. The second aspect is the development of a new measuring technique
for minority carrier lifetimes in semiconductors. This technique is becoming
increasingly necessary as the amount of surface recombination is reduced. This
project would suit a student who is interested in electronics and simple computer
programming and the building of precision equipment. Any interested student should
choose either the passivation part OR the new measurement technique part. It will
not be possible for a single student to do both.
Control of impurity defect interactions for cheaper silicon solar cells
Peter Wilshaw
Most of the silicon used for silicon solar cells (the dominant technology) comes in the
form of multi-crystalline wafers sliced from ingots of cast silicon. This material
contains relatively high concentrations of metallic impurities, dislocations and grain
boundaries, all of which enhance electron-hole recombination and hence reduce
solar cell efficiency. This project aims to develop a range of novel ideas originating
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from the Semiconductor Group in Oxford. The research will be performed performed
in collaboration with leading suppliers of silicon to the photovoltaic industry and will
involve some work in a semiconductor clean room.
The production of semi-insulating silicon
Peter Wilshaw/Kanad Mallik
This project will provide an opportunity to research the making of semi-insulating
(resistivity of 10-300kohm-cm) silicon-on-insulator (SOI) substrates grown by the
Czochralski technique for microwave monolithic integrated circuits (MMIC). This has
been identified as a novel substrate material in the ITRS Roadmap and has the
potential to bring about a paradigm shift in the semiconductor industry.
Structure Property Relationships in Superengineering Polymers
Robin Young
High performance “super engineering” polymers are becoming invaluable in a range
of demanding applications such as in the aerospace and biomedical sectors.
Standard PEEK (poly ether ether ketone) and PEKK (poly ether ketone ketone) are
commercially available from a number of sources. The project will compare the
physical, mechanical and thermal properties of a range of Ketonex’s polymers to
commercially available materials such as Victrex®PEEK™, PEKK and Ultem® (poly
ether imide). A vital aspect will be the measurement of the melt stability of the
materials at processing temperatures. A range of analytical techniques will be used,
to include DSC, TGA, mechanical testing, rheology, inherent viscosity and particle
size analysis. The results will be used to interpret the differences in observed
behaviours. Ketonex Limited will act as an industrial partner for this project.
Controlling and optimising properties in Carbon Carbon Composites
Robin Young/Nicole Grobert
Novel processing routes for carbon fibre-carbon matrix composite materials are
emerging and are fast finding commercial application in demanding environments.
This is an important class of materials with applications in automotive, aviation and
space. Novel applications are dependent on the thermal properties of the materials
demanding exceptionally high or low specific thermal conductivity. The project aims
to identify and optimise the factors controlling thermal conductivity in a range of
material variants with and without CNT additions. Techniques include microscopy,
XRD, thermal conductivity measurement, hot pressing. The industrial partner is
FrenoCarbon.
Decompostion behaviours in ammonium borohydride hydrogen storage
systems
Robin Young
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We are looking at different polymer based materials to act as filters to purity
hydrogen from a contaminated gas stream. These operate on solution diffusion
mechanism; where the gas adsorbs on the surface diffuses through the polymer and
then desorbs from the other side. The performance depends on the solubility and
diffusion constants of the different gases within the polymer.
The project will be to search for new filter materials, and then develop and test them
to optimise their performance for use in a real application. It will involve making the
filters and testing them as well as characterising the materials using techniques such
as x-ray diffraction and electron microscopy. It will also be necessary to develop
simple models to understand how they are operating, both to assist with the
development and the search.
Cella Energy is a spin-out of the Rutherford Appleton Laboratory, University College
London and Oxford University. Its aim is to develop safe, low-cost hydrogen storage
materials for use with fuel cells in battery replacement projects and automotive
power applications. It currently has 21 employees/ contractors and students at two
sites: one at the Rutherford Appleton Laboratory and one at the Kennedy Space
Center in Florida. The project work will be done with the Cella Team at the UK
laboratory.