nist project final report
TRANSCRIPT
Quantifying microstructural features and finding structure-property linkages in aging process of Al6061
Ali Khosravani
Jordan Weaver
ME8883 Materials Informatics
Introduction
Alloys in this group have high strength-to-weight ratio Good weldability good formability good corrosion resistance
Solid Solutio
n
Coherent Precipitates
(β”)
Partially Coherent(β
’)
Incoherent Precipitates(
β)
Soft
Strength increase Peak Strength Overaged
Application Aircraft fittings
camera lens mounts
electrical fittings and connectors
brake pistons, hydraulic pistons
valves and valve parts
bike frames.
Strengthen by Precipitation of Mg2Si, higher levels of Mg2Si leeds to higher strength
MicrostructureMicrostructural features of
impact exist at different length scales
• Coherent GP zones and semi-coherent precipitate particles (TEM or SEM)
Volume fraction
Size (nm)
Aspect ratio
Spacing (nm)
• Al-Fe-Si-type constituent particles (OM) Volume fraction
Size (microns)
Aspect ratio
Spacing (microns)
• Grain structure, including degree of recrystallization and texture (EBSD)
Size (microns)
Aspect ratio
Texture
Mechanical Properties and microstructure
Mechanical Properties is a result of :
Precipitate hardening strengthen material
Precipitate Volume fraction Precipitate Size (nm) Precipitate Aspect ratio Precipitate Spacing (nm) Particle Volume fraction Particle Size (microns) Particle Aspect ratio Particle Spacing (microns) Grain structure Grain Size Grain Aspect ratio Texture Grain Boundary
Experiments
Mechanical testing Uniaxial Tensile Test
Five tests were run for each condition.
ASTM E8-13a (Round specimens with a diameter and gage length of 0.25” of 1” respectively.
The machine was run at a constant cross head speed to achieve a strain rate of 0.005 in/in /s
Al 6061 Specimen Type
Average Yield
Strength (ksi)
Average Ultimate Tensile Strength
(ksi)400F HT 43.136 46.400525F HT 26.022 33.188650F HT 13.493 24.439775F HT 8.633 20.321AR RD 44.114 47.660
Microstructural Datasets
EBSD 75 scans and combined
into scan size of7x7 mm2
4 µm resolution
SEM 10 BSE images at random
regions
View field: 100x100 µm2
Optical Microscope (OM) 10 images at random
regions
View field: 800x600 µm2
EBSD dataset
Grain aspect ratio =
• Grain size distribution Grain size distribution is
calculated based on number of pixels in each grain.
• Grain aspect ratio distribution The aspect ratio is defined
as the length of the minor axis divided by the length of the major axis and thus ranges from 0 to 1
Original Image Corrected Image Segmented Image
400F
775F
OM dataset Images were corrected and segmented Volume fraction, Size, Aspect ratio, and Spacing of
particle were measured
Chord Length
0 50 100 150 200 250 300 350 400 450 5000
1
2
3
x 10-4
Number of Pixels
Freq
uenc
y
AR
400 F
525 F
650 F
775 F
Calculating chord lengths row by row on x direction and column by column in y directions on binary images
Performing this operation over 10 images
TEM images required to provide information about precipitate in higher resolution and information about precipitate/matrix interface
SEM dataset
Images were segmented Volume fraction, Size, and Spacing of particle were
measured
2-Point Statistics vs Measures Values
2-point statistics contains all information about particle size, aspect ratio, volume fraction and their spacing.
PCA can be performed on 2-point statistic instead of the calculated parameters (Size, spacing, aspect ratio)
PCA on 2-Point Statistics
-40 -20 0 20 40 60-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
PC 1
PC
2
AR400 F525 F650 F775 F
-40 -20 0 20 40 60-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
PC 1
PC
3
-0.3 -0.2 -0.1 0 0.1 0.2-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
PC 1
PC
2
AR400 F525 F650 F775 F
-0.3 -0.2 -0.1 0 0.1 0.2-0.03
-0.02
-0.01
0
0.01
0.02
0.03
PC 1
PC
3
PCA on Chord length(Particle Spacing),
Size, Aspect Ratio
-30 -20 -10 0 10 20 30 40 50-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
PC 1
PC
2
AR400 F525 F650 F775 F
-30 -20 -10 0 10 20 30 40 50-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
PC 1
PC
3
PCA on 2-Point Statistics
Averaging on Measured Values Image dimensions from each OM,
EBSD, and SEM datasets are
different.
The images were taken at random
regions on sample EBSD
OMSEM
To combine all Data together, OM and SEM datasets need to be averaged out
fr00
150 200 250
150
200
250
0.01
0.02
0.03
0.04
fr11
150 200 250
150
200
2500.92
0.93
0.94
0.95
-50 0 50
50
-50
0
0
-50
50
0
-50
50
0
-50
50
0
-50
50
0
-50
50
0
-50
50
0
-50
50
-50
0
50
0
-50
50
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
0.04
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
150 200 250
150
200
250
0.01
0.02
0.03
050
-50050
-50050
-50
050-500
50
-50
050
-50050
-50050
-50
050
-50
2-point Statistics in quantifying each microstructural features
2-point statistics contains all information about particle size, aspect ratio, volume fraction and their spacing.
PCA can be performed on 2-point statistic instead of the calculated parameters (Size, spacing, aspect ratio)
PCA on Average values from optical images (2-Point Statistics) and EBSD values (Grain size, Grain
aspect ratio)
-20 -10 0 10 20 30 40-0.15
-0.1
-0.05
0
0.05
0.1
PC 1
PC
2
AR
400 F
525 F650 F
775 F
-20 -10 0 10 20 30 40-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
PC
3
PC 1
Principal Component Analysis
Structure-property (Yield Strength) linkages
-20 0 20 405
10
15
20
25
30
35
40
45
Yie
ld S
tre
ng
th (
ksi)
PC 1
AR400 F525 F650 F775 F
-0.2 -0.1 0 0.1 0.25
10
15
20
25
30
35
40
45
Yie
ld S
tre
ng
th (
ksi)
PC 2
-0.1 -0.05 0 0.05 0.15
10
15
20
25
30
35
40
45
Yie
ld S
tre
ng
th (
ksi)
PC 3
Structure- property (Ultimate Tensile Strength) linkages
-20 0 20 4020
25
30
35
40
45
50
Ulti
ma
te T
en
sile
Str
en
gth
(ksi
)
PC 1
AR400 F525 F650 F775 F
-0.2 -0.1 0 0.1 0.220
25
30
35
40
45
50
Ulti
ma
te T
en
sile
Str
en
gth
(ksi
)
PC 2
-0.1 -0.05 0 0.05 0.120
25
30
35
40
45
50
Ulti
ma
te T
en
sile
Str
en
gth
(ksi
)
PC 3
Future work
High Throughput Experiments
EBSD
OMSEM
Local propertiesMeasuring local properties through nano- and miro-indentation
Local microstructureCollecting EBSD and OM images at the same area, and SEM images at the known locations within marks
Acknowledgments
Dr. Surya Kalidindi Dr. Tony Fast
Jordan Weaver Jon Yabansu Ahmet Cecen Andrew Castillo