lecture_5-b
DESCRIPTION
structure and properties of materialTRANSCRIPT
10/12/2010
1
October 12, 20101
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
Lecture_5-b
October 12, 20102
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
10/12/2010
2
October 12, 20103
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
October 12, 20104
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
Glass is an inorganic
product of fusion that has
cooled to a rigid condition
without crystallizing and,
therefore, has no melting
point as such.
Glass Transition Phenomena
The glass transition
temperature, “Tg “, is the
temperature at which an
amorphous solid, such as
glass or a polymer, becomes
brittle on cooling, or soft on
heating
10/12/2010
3
October 12, 20105
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
October 12, 2010
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam 6
1. The Working Point — the temperature at which glass has a
viscosity of 104 poises. At this temperature, glass is soft enough for
most forming operations.
2. The Softening Point — the temperature at which glass has a
viscosity of 4x107 poises, is the maximum temperature at which a
glass piece may be handled without causing significant dimensional
alternation.
3. The Annealing Point — is the temperature at which the viscosity
is 1013 poises at this temperature the internal stress caused by rapid
cooling from forming temperatures may be substantially removed
in a matter of minutes (15 min.).
4. The Strain Point — corresponding to the temperature at which
the viscosity becomes 3x 1014 poises; for temperatures below the
strain point, fracture will occur before the onset of plastic
deformation. The glass transition temperature will be above the
strain point
There are four temperatures that are of interest to the
glassblower. They are:
10/12/2010
4
October 12, 20107
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
Paving
Shell
wine storage
Chimney Caps and handmade clay roof
Yoda of Star WarsPottery
October 12, 20108
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
10/12/2010
5
October 12, 20109
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
October 12, 201010
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
Agitated Pressure Filters
Valves
Pressure Vessel Clamps
Gap Fillers
10/12/2010
6
October 12, 201011
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
October 12, 201012
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
In the most general sense of the word, a cement is a
binder, a substance which sets and hardens
independently, and can bind other materials together.
The most important use of cement is the production of
mortar and concrete - the bonding of natural or artificial
aggregates to form a strong building material which is
durable in the face of normal environmental effects.
Cement should not be confused with concrete as the term
cement explicitly refers to the dry powder substance.
Upon the addition of water and/or additives the mixture is
no longer referred to as cement but concrete, regardless if
aggregates have already been added or not.
10/12/2010
7
October 12, 201013
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam
An optical fiber (or fiber) is a glass
or plastic fiber designed to guide
light along its length. Optical fibers
are widely used in fiber-optic
communication, which permits
transmission over longer distances
and at higher data rates than other
forms of communications. Fibers are
used instead of metal wires because
signals travel along them with less
loss, and they are immune to
electromagnetic interference. Optical
fibers are also used to form sensors,
and in a variety of other
applications.
Study well:Crystallization, Melting,
………….: page 446 to 451
Types of Ceramics:
page 540 to 547
Optical Fibers:
page 548 to 549
Piezoelectric ceramics
page 550
Diamond and graphite
page 550 to 551
October 12, 2010
ENGR 230
Structure and Properties of Materials
Nahid Abdel Salam 14