This document analyzes changes in the microstructure of Al6061 as it ages. Images of samples annealed at different temperatures (400F, 525F, 650F, 775F) were taken and analyzed to quantify features like constituent particle volume fraction and spacing. Principal component analysis was used to identify correlations between measured microstructural parameters and how they change with increasing annealing temperature.

1. Quantifying microstructural features
in aging process of Al6061
Ali Khosravani
Jordan Weaver

2. Original Image Corrected Image Segmented Image
400
775

3. Volume fraction- Constituent particle
AR 400F 525F 650F 775F
Image 1 0.032904 0.041857 0.036041 0.051641 0.097341
Image 2 0.023965 0.043686 0.035519 0.060976 0.103627
Image 3 0.024079 0.040578 0.031837 0.054671 0.111044
Image 4 0.027179 0.039005 0.045656 0.054723 0.092842
Image 5 0.027323 0.041474 0.036051 0.054555 0.106871
Image 6 0.024258 0.038561 0.034232 0.057636 0.106811
Image 7 0.028309 0.036217 0.028897 0.054658 0.089563
Image 8 0.021637 0.03788 0.029157 0.058748 0.084825
Image 9 0.026702 0.035803 0.099341 0.104465
Image 10 0.020928 0.041351 0.046461 0.089996
Average 0.025728 0.039641 0.034674 0.059341 0.098739

4. Particle Spacing- Chord length on matrix
0 50 100 150 200 250 300 350 400 450 500
3
2
1
0
x 10
-4
Number of Pixels
Frequency
AR
400 F
525 F
650 F
775 F

5. 150
200
250
0.04
0.03
0.02
150
200
250
150 200 250
0.04
0.03
0.02
0.01
150
200
250
0.04
0.03
0.02
150
200
250
150 200 250
0.04
0.03
0.02
0.01
150
200
250
0.04
0.03
0.02
150
150 200 250
0.04
0.03
0.02
0.01
150
200
250
0.03
0.02
150
200
250
150 200 250
0.03
0.02
0.01
150
200
250
0.04
0.03
0.02
150
200
250
150 200 250
0.04
0.03
0.02
0.01
150
200
250
0.03
0.02
200
150 200 250
0.03
0.02
0.01
150
200
250
0.03
0.02
150
200
250
150 200 250
0.03
0.02
0.01
150
200
250
0.03
0.02
150
200
250
150 200 250
0.03
0.02
0.01
150
200
250
0.03
0.02
250
150 200 250
0.03
0.02
0.01
0.04
0.03
0.02
200 250
0.01
150
200
250
0.04
0.03
0.02
150 200 250
0.01
150
200
250
0.04
0.03
0.02
150 200 250
0.01
0.03
0.02
200 250
0.01
150
200
250
0.04
0.03
0.02
150 200 250
0.01
150
200
250
0.03
0.02
150 200 250
0.01
0.03
0.02
200 250
0.01
150
200
250
0.03
0.02
150 200 250
0.01
150
200
250
0.03
0.02
150 200 250
0.01
0.01
150 200 250
0.01
150 200 250
0.01
0.01
150 200 250
0.01
150 200 250
0.01
0.01
150 200 250
0.01
150 200 250
0.01
00
f
r
150 200 250
0.04
0.03
0.02
0.01
150
200
250
2-point statistics on OM and averaging statistics

6. 00
f
r
150
200
250
150 200 250
0.03
0.02
0.01
11
f
r
150
200
250
150 200 250
0.96
0.95
0.94
0.93

7. 4
2
0
-2
-4
-6
-8
-10
-2 -1.5 -1 -0.5 0 0.5 1
x 10
-3
-12
x 10
-4
PC 1
PC 2
AR
400 F
525 F
650 F
775 F
2
1.5
1
0.5
0
-0.5
-1
-2 -1.5 -1 -0.5 0 0.5 1
x 10
-3
-1.5
x 10
-4
PC 1
PC 3
PCA on Chord Length

8. 0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-50 -40 -30 -20 -10 0 10 20 30
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
AR
400 F
525 F
650 F
775 F
PCA on 2 point Stats + Chord Length
-0.8
PC 1
PC 2
-50 -40 -30 -20 -10 0 10 20 30
PC 1
PC 3

9. 0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-30 -20 -10 0 10 20 30 40 50
PC 1
PC 2
AR
400 F
525 F
650 F
775 F
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-30 -20 -10 0 10 20 30 40 50
PC 1
PC 3
PCA on 2 point Stats