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Alcoa Power and Propulsion
Effect of Testing Speed on Several Alloys
Susan MorfordAlcoa Howmet Research Center
Alcoa Power and PropulsionAlcoa Power and Propulsion
Overview of Methodology and Analysis Approach
• Design of Experiment– Alloys– Strain rate / Crosshead speeds– Three specimens for each test condition
• Analysis methodology– Graphical results
• Ultimate Strength (KSI)• 0.2% Offset Yield Strength (KSI)• Percent Elongation (%)• Reduction of Area (%)
– ANOVA to evaluate statistical significance of results• Summary of results
Alcoa Power and PropulsionAlcoa Power and Propulsion
Design of Experiment
• Test Conditions (Full-factorial – all combinations were tested)– Strain rates
• A – 0.005 inch/inch/minute• B – 0.015 inch/inch/minute• C – 0.050 inch/inch/minute
– Crosshead rates• 1 – 0.05 inch/minute• 2 – 0.45 inch/minute
– Strain Rate / Crosshead rates tested• A1, A2, B1, B2, C1, C2
– Strain rate measured with an extensometer directly attached to the reduced section of specimen; removed at 0.4% offset
Alcoa Power and PropulsionAlcoa Power and Propulsion
Design of Experiment
• Equipment / Instrumentation– Tinius Olsen 60,000
pound load frame with Test Navigator version 7 software and 398 controller
– Extensometer – 1 inch gauge length attached to reduced section of specimen
Alcoa Power and PropulsionAlcoa Power and Propulsion
Design of Experiment
Alloy Base Alloy Alloy Type Specimen Configuration
17-4PH Iron Cast Machined
CMSX-4 ® Nickel Cast Machined
Alloy 718 Nickel/Iron Cast Cast to Size
Alloy 718 Nickel/Iron Wrought Machined
Stellite 31® Cobalt Cast Cast to Size
Ti-6-4 Titanium Cast Cast to Size
Alcoa Power and PropulsionAlcoa Power and Propulsion
Analysis Methodology - Graphical
17-4PH - Ultimate Tensile Strength (UTS)
166
168
170
172
174
176
A1 A2 B1 B2 C1 C2
Strain Rate / Crosshead Speed
KSI
Center Line: Mean of three (3) Specimens Spread: ± 1 Standard Deviation
Alcoa Power and PropulsionAlcoa Power and Propulsion
Analysis Methodology - ANOVA
• Summary of ANOVA table obtained from SAS software
• Interactions identified as significant are highlighted
Factor Degree of Freedom Percentiles of theF distribution
F* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.60 0.60 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 10.89 10.89 > 4.75 Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.69 0.69 ≤ 3.89 Not Significant
Alcoa Power and PropulsionAlcoa Power and Propulsion
Ultimate Strength – 17-4PH
17-4PH - Ultimate Tensile Strength (UTS)
166
168
170
172
174
176
A1 A2 B1 B2 C1 C2
Strain Rate / Crosshead Speed
KS
I
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.60 0.60 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 10.89 10.89 > 4.75 Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.69 0.69 ≤ 3.89 Not Significant
Alcoa Power and PropulsionAlcoa Power and Propulsion
0.2% Offset Yield Strength – 17-4PH
17-4PH - 0.2% Offset Yield Strength
125
127
129
131
133
135
A1 A2 B1 B2 C1 C2
Strain Rate / Crosshead Speed
KS
I
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 22.34 22.34 > 3.89 Significant
Crosshead 1 F(0.95,1,12) = 4.75 3.06 3.06 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 2.37 2.37≤ 3.89 Not Significant
Alcoa Power and PropulsionAlcoa Power and Propulsion
Percent Elongation – 17-4PH
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.24 0.24 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 4.57 4.57 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 1.68 1.68 ≤ 3.89 Not Significant
17-4PH - Elongation
11.5
12.0
12.5
13.0
A1 A2 B1 B2 C1 C2
Strain Rate / Crosshead Speed
Pe
rce
nt
Alcoa Power and PropulsionAlcoa Power and Propulsion
Percent Reduction of Area – 17-4PH
17-4PH - Reduction of Area
60
61
62
63
64
65
A1 A2 B1 B2 C1 C2
Strain Rate / Crosshead Speed
Pe
rce
nt
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.47 0.47 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 1.62 1.62 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 5.09 5.09 > 3.89 Significant
Alcoa Power and PropulsionAlcoa Power and Propulsion
Ultimate Strength – CMSX-4 ®
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.10 0.10 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.00 0.00 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.06 0.06 ≤ 3.89 Not Significant
CMSX-4® - UTS
125
135
145
155
165
175
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Alcoa Power and PropulsionAlcoa Power and Propulsion
0.2% Offset Yield Strength – CMSX-4 ®
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.03 0.03 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.47 0.47 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.16 0..16 ≤ 3.89 Not Significant
CMSX-4® - 0.2% Yield Strength
120
125
130
135
140
145
150
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Alcoa Power and PropulsionAlcoa Power and Propulsion
Elongation – CMSX-4 ®
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.27 0.27 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 3.12 3.12 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.63 0.63 ≤ 3.89 Not Significant
CMSX-4® - Elongation
5
10
15
20
25
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Alcoa Power and PropulsionAlcoa Power and Propulsion
Reduction of Area – CMSX-4 ®
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.61 0.61≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.12 0.12 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 5.0 5.0 > 3.89 Significant
CMSX-4® - Reduction of Area
5
10
15
20
25
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Alcoa Power and PropulsionAlcoa Power and Propulsion
Ultimate Strength – Cast Alloy 718
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.26 0.26 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 10.47 10.47 > 4.75 Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.37 0.37 ≤ 3.89 Not Significant
Cast Alloy 718 - UTS
150
155
160
165
170
175
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Alcoa Power and PropulsionAlcoa Power and Propulsion
0.2% Offset Yield Strength – Cast Alloy 718
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 1.41 0.26 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.00 0.00 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 1.02 0.37 ≤ 3.89 Not Significant
Cast Alloy 718 - 0.2% Yield Strength
138
140
142
144
146
148
150
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Alcoa Power and PropulsionAlcoa Power and Propulsion
Elongation – Cast Alloy 718
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.89 0.89 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 1.92 1.92 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.58 0.58 ≤ 3.89 Not Significant
Cast Alloy 718 - Elongation
0
2
4
6
8
10
12
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Alcoa Power and PropulsionAlcoa Power and Propulsion
Reduction of Area – Cast Alloy 718
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.84 0.84 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 3.17 3.17 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.35 0.35 ≤ 3.89 Not Significant
Cast Alloy 718 - Reduction of Area
0
5
10
15
20
25
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Alcoa Power and PropulsionAlcoa Power and Propulsion
Ultimate Strength – Wrought Alloy 718
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.78 0.78 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.00 0.00 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 3.21 3.21 ≤ 3.89 Not Significant
Wrought Alloy 718 - UTS
203204205206207208209210211
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Alcoa Power and PropulsionAlcoa Power and Propulsion
0.2% Offset Yield Strength – Wrought Alloy 718
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 3.64 3.64 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.11 0.11 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 2.89 2.89 ≤ 3.89 Not Significant
Wrought Alloy 718 - 0.2% Yield Strength
168
170
172
174
176
178
180
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Alcoa Power and PropulsionAlcoa Power and Propulsion
Elongation – Wrought Alloy 718
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.16 0.16 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 373.48 373.48 > 4.75 Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 1.11 1.11 ≤ 3.89 Not Significant
Wrought Alloy 718 - Elongation
16.0
17.0
18.0
19.0
20.0
21.0
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Alcoa Power and PropulsionAlcoa Power and Propulsion
Reduction of Area – Wrought Alloy 718
Factor Degree of FreedomPercentiles of theF distribution
F* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.16 0.16 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 13.21 13.21 > 4.75 Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.26 0.26 ≤ 3.89 Not Significant
Wrought Alloy 718 - Reduction of Area
38.5
39.0
39.5
40.0
40.5
41.0
41.5
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Alcoa Power and PropulsionAlcoa Power and Propulsion
Ultimate Strength – Stellite 31®
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.03 0.03 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 3.58 3.58 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 1.25 1.25 ≤ 3.89 Not Significant
Stellite 31® - UTS
110
115
120
125
130
135
140
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Alcoa Power and PropulsionAlcoa Power and Propulsion
0.2% Offset Yield Strength – Stellite 31®
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 2.79 2.79 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.07 0.07 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.52 0.52 ≤ 3.89 Not Significant
Stellite 31® - 0.2% Yield Strengh
75
80
85
90
95
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Alcoa Power and PropulsionAlcoa Power and Propulsion
Elongation – Stellite 31®
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.02 0.02 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.37 0.37 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.82 0.82 ≤ 3.89 Not Significant
Stellite 31® - Elongation
4
5
6
7
8
9
10
11
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Alcoa Power and PropulsionAlcoa Power and Propulsion
Reduction of Area – Stellite 31®
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.51 0.51 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 2.53 2.53 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.06 0.06 ≤ 3.89 Not Significant
Stellite 31® - Reduction of Area
4
6
8
10
12
14
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Alcoa Power and PropulsionAlcoa Power and Propulsion
Ultimate Strength – Ti-6-4
Ti-6-4 - UTS
134
136
138
140
142
144
146
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.30 0.30 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 9.78 9.78 > 4.75 Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.59 0.59 ≤ 3.89 Not Significant
Alcoa Power and PropulsionAlcoa Power and Propulsion
0.2% Offset Yield Strength – Ti-6-4
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 13.20 13.20 > 3.89 Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.03 0.03 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 0.67 0.67 ≤ 3.89 Not Significant
Ti-6-4 - 0.2% Yield Strength
120
122
124
126
128
130
132
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
KS
I
Alcoa Power and PropulsionAlcoa Power and Propulsion
Elongation – Ti-6-4
Ti-6-4 - Elongation
6
8
10
12
14
16
18
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 0.00 0.00 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 0.61 0.61 ≤ 4.75 Not Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 2.68 2.68 ≤ 3.89 Not Significant
Alcoa Power and PropulsionAlcoa Power and Propulsion
Reduction of Area – Ti-6-4
Ti-6-4 - Reduction of Area
6
11
16
21
26
31
36
A1 A2 B1 B2 C1 C2
Strain Rate / Cross Head Speed
Perc
en
t
Factor Degree of FreedomPercentiles of the
F distributionF* Conclusion Result
Strain 2 F(0.95,2,12) = 3.89 2.24 2.24 ≤ 3.89 Not Significant
Crosshead 1 F(0.95,1,12) = 4.75 15.0 15.0 > 4.75 Significant
Strain * Crosshead 2 F(0.95,2,12) = 3.89 2.00 2.00 ≤ 3.89 Not Significant
Alcoa Power and PropulsionAlcoa Power and Propulsion
ANOVA Summary for Significant Relationships
Strain Crosshead Strain*Crosshead
17-4PH 0.2% YS UTS ROA
CMSX-4® ROA
Alloy 718 - Cast UTS
Alloy 718 - Wrought% Elongation, ROA
Stellite 31 ®
Ti-6-4 0.2% YS UTS, ROA
Alcoa Power and PropulsionAlcoa Power and Propulsion
Variation in Time to Fracture
Time to Fracture
012345678
A1 A2 B1 B2 C1 C2
Strain Rate / Crosshead Speed
Tim
e in
Min
ute
s
17-4PH
CMSX-4®
Alloy 718 - Cast
Alloy 718 - Wrought
Stellite 31®
Ti-6-4
Alcoa Power and PropulsionAlcoa Power and Propulsion
Conclusions
• Five of the six alloys evaluated at room temperature had at least one tensile property that is dependent on the speed of testing
• ASTM E21-05 Standard Test Methods for Elevated Tension Test of Metallic Materials– Section 9.6 addresses “Strain Measurement and Strain Rate”
• Tensile properties of materials at elevated temperature are affected by the rate of deformation
• A similar statement should be included in ASTM E8
Alcoa Power and PropulsionAlcoa Power and Propulsion
Recommendations
• Allow use of ASTM E-21-05 9.6.1.1 as an option or as a recommendation for room temperature testing– “During yield strength determination, maintain the stain rate in
the uniform section of the specimen at 0.005 ± 0.002 /min. After yield strength determination, increase the crosshead motion to 0.05 ± 0.01 times the adjusted length of the reduced section of the specimen per minute.”
• Add an Appendix to ASTM E8 and E21 addressing speed of testing