Experimental Method; EFFECT OF ALLOYING ADDITIONS AND AGING CONDITIONS ON THE HARDNESS OF ALUMINUM ALLOY

1. EFFECT OF ALLOYING ADDITIONS AND
AGING CONDITIONS ON THE
HARDNESS (HB) OF 319 (ALUMINUM)
ALLOYS
By Andi Firdaus Sudarma
ID No.: 432107963
ME-508 Experimental Methods in ME
DR. Basharat Salim (Lecturer)

2. INTRODUCTION

3. Table 1. Chemical composition limits of
aluminum 319. [3]

4. EXPERIMENTAL DESIGN

5. Experimental Procedure
Heat
Quenching
Ingot Treatment
(Water@65OC)
(8h@495OC)
Melting Casting Aging
Pure Argon Hardness
Adding Alloys
Degassing Measurement

6. Heat Treatment and Aging Scheme

7. Experimental Aging Matrix
H1: aging at 180oC up to 2 hours.
H2: aging at 180oC up to 8 hours.
H3: aging at 220oC up to 2 hours.
H4: aging at 220oC up to 8 hours.

8. DATA & RESULT

9. Data Result
Alloy Factors Combination Aging Condition
Code
%Mg %V.F Sr-ppm H1 H2 H3 H4
18 - - - 117 119 108 103
20 + - - 131.5 132.5 119 116
19 - + - 117.5 123 106 101
21 + + - 137.5 133.5 127 112
18s - - + 108.5 109 94 96.5
20s + - + 120.5 119 114 99
19s - + + 117.5 115 96 95.5
21s + + + 127 128.5 116 101.5

10. Notation
• %Mg (+) maximum value of magnesium
contains (~0.27%)
(-) minimum value of magnesium
contains (~0.1%)
• %V.F (+) Fe-type morphology: α-Fe and β-Fe
(-) Fe-type morphology: α-Fe
• Sr-ppm (+) Strintium modified
(-) No modification

11. Anova Table
Source of Sum of Degree of Mean
Fo Ft
Variation Square Freedom Square
Alloy 2131.594 7 304.513 24.077 2.51
Aging
2177.406 3 725.802 57.387 3.10
Condition
Non
5.766 1 5.766 0.456 4.35
Addivity
Error 252.952 20 12.648
Total 4567.719 31

12. Hypothesis

13. • With confidence level at 95%, non addivity
comparison of F value, we have Fo < Ft, so the
null hypothesis is accepted. It mean that there is
no interaction between treatment A and B. If
there is no interaction then (τβ)ij = 0 for all i and
j.
• Comparing the F value that we get from
observation and F value from table, the
correlation is Fo > Ft, it mean that there
significant mean effect of treatment A and
treatment B.

14. Plot of Hardness vs. Aging Condition
150
140
Alloy 18
130
Alloy 20
Alloy 19
Hardness
120
Alloy 21
110 Alloy 18s
100 Alloy 20s
Alloy 19s
90 Alloy 21s
80
H1 H2 H3 H4 Aging Condition

15. Plot of Hardness vs. Alloy Addition
150
140
130
120 H1
H2
110
H3
100 H4
90
80
18 20 19 21 18s 20s 19s 21s

16. Treatment A Mean Comparison (LSD)
Mean Mean Less/Mo
LSD Remark
Comparison Difference re
y1-y3 -0.125 < 5.190 Not significant
y1-y6 -1.375 < 5.190 Not significant
y2-y4 -2.75 < 5.190 Not significant
y3-y6 -1.25 < 5.190 Not significant
y5-y7 -4 < 5.190 Not significant
y6-y8 -5.125 < 5.190 Not significant

17. Treatment B Mean Comparison (LSD)
Mean Mean Less/
LSD Remark
Comparison Difference More
y1-y2 0.3125 < 3.670 Not significant
y1-y3 12.125 > 3.670 Significantly Different
y1-y4 19.0625 > 3.670 Significantly Different
y2-y3 12.4375 > 3.670 Significantly Different
y2-y4 19.375 > 3.670 Significantly Different
y3-y4 6.9375 > 3.670 Significantly Different

18. DISCUSSION

19. Responses for Alloy Containing
Alloy Code Factors Combination Mean
%Mg %V.F Sr-ppm Hardness
18 - - - 111.75
20 + - - 124.75
19 - + - 111.875
21 + + - 127.5
18s - - + 102
20s + - + 113.125
19s - + + 106
21s + + + 118.25

20. Mean Value of Treatment B
H1 H2 H1 H1
(Temp- (Temp-180, (Temp-220, (Temp-220,
180, Time-2h) Time-8h) Time-2h) Time-8h)
977 979.5 880 824.5

21. CONCLUSION

22. • The main effect of alloy addition that is, Mg
addition and volume fraction addition to alloy has
increased the hardness number significantly. The
contradictive is happen to Sr-modification, it cause
the hardness number decrease.
• The main effect of aging time and aging
temperature on the hardness is described as follow;
at temperature 180oC, the main effect of aging time
is not significant. At temperature 220oC, increasing
the aging time will effect to hardness, which is
decreasing. With the same of aging temperature,
increasing temperature will decrease the hardness.

23. Thank you