nist project class report
TRANSCRIPT
Quantifying microstructural features in aging process
of Al6061
Ali KhosravaniJordan Weaver
Project Goal:Extract Microstructure-Property-Process linkages in aging of Al6061 aluminum alloy through multi model experimental methods
Mechanical testing: • Tensile testing • Spherical indentation
Microscopy technique:• SEM• EBSD• OM
• Al6061 application• Aging process• Mechanical Properties
Salient Microstructural Features
• Grain size, shape, and texture
• Constituent particle size,
volume fraction, distribution,
and spacing
• Precipitate size, volume
fraction, and spacing
Grain Size, Shape, and TextureInverse pole figure mapAn inverse pole figure shows the position of a sample direction relative to the crystal reference frame. In terms of IPF map in EBSD, each color represent three euler angle that transform the sample frame to the crystal frame.
As-received sample
Grain size distribution
Grain size distribution is calculated based on equivalent diameter values. The equivalent diameter is the diameter of a circle that gives the same area as the one for that grain.
D
As-received sample
Aged at 400F for 2 hrs
Aged at 525F for 2 hrs
Aged at 650F for 2 hrs
Aged at 775F for 2 hrs
Grain aspect ratio distribution
One measure of the shape of grains in EBSD scan is the aspect ratio. 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
a b
Grain aspect ratio =
As-received sample
Aged at 400F for 2 hrs
Aged at 525F for 2 hrs
Aged at 650F for 2 hrs
Aged at 775F for 2 hrs
TextureThe full 3D representation of crystallographic texture is given by the orientation distribution function (ODF). The ODF is defined as the volume fraction of grains with a certain orientation g.
As-r
ecei
ved
sam
ple
Aged
at 4
00F
for 2
hrs
Aged
at 5
25F
for 2
hrs
Aged
at 6
50F
for 2
hrs
Aged
at 7
75F
for 2
hrs
Constituent particle size, volume fraction, distribution, and spacing
Image Segmentation
Original Image Corrected Image Segmented Image
400
775
AR 400F 525F 650F 775FImage 1 0.032904 0.041857 0.036041 0.051641 0.097341Image 2 0.023965 0.043686 0.035519 0.060976 0.103627Image 3 0.024079 0.040578 0.031837 0.054671 0.111044Image 4 0.027179 0.039005 0.045656 0.054723 0.092842Image 5 0.027323 0.041474 0.036051 0.054555 0.106871Image 6 0.024258 0.038561 0.034232 0.057636 0.106811Image 7 0.028309 0.036217 0.028897 0.054658 0.089563Image 8 0.021637 0.03788 0.029157 0.058748 0.084825Image 9 0.026702 0.035803 0.099341 0.104465Image 10 0.020928 0.041351 0.046461 0.089996Average 0.025728 0.039641 0.034674 0.059341 0.098739
Volume fraction- Constituent particle
0 50 100 150 200 250 300 350 400 450 5000
1
2
3
x 10-4
Number of Pixels
Fre
que
ncy
AR
400 F
525 F
650 F
775 F
Particle Spacing- Chord length on matrix
-2 -1.5 -1 -0.5 0 0.5 1
x 10-3
-12
-10
-8
-6
-4
-2
0
2
4x 10
-4
PC 1
PC
2
AR400 F525 F650 F775 F
-2 -1.5 -1 -0.5 0 0.5 1
x 10-3
-1.5
-1
-0.5
0
0.5
1
1.5
2x 10
-4
PC 1
PC
3
PCA on Chord Length
-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 Stats
PCA on 2 point Stats + Chord Length-50 -40 -30 -20 -10 0 10 20 30
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
PC 1
PC
2
-50 -40 -30 -20 -10 0 10 20 30-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
PC 1
PC
3
AR400 F525 F650 F775 F
Precipitate size, volume fraction, and spacing
-30 -25 -20 -15 -10 -5 0 5 10-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
PC 1
PC
2
525 F650 F775 F
-0.5 0 0.5-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
PC 2
PC
3
High Throughput Experiments
• Local properties• Local microstructure
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