Alcoa Power and Propulsion
Effect of Testing Speed on Several Alloys
Susan Morford
Alcoa Howmet Research Center
susan.morford@alcoa.com
231.894.7704
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 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 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 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 Propulsion
Analysis Methodology - Graphical
17-4PH - Ultimate Tensile Strength (UTS)
176
KSI
174
172
170
168
166
A1
A2
B1
B2
C1
C2
Strain Rate / Crosshead Speed
Spread: ± 1 Standard Deviation
Center Line: Mean of three (3) Specimens
Alcoa Power and Propulsion
Analysis Methodology - ANOVA
Factor
Degree of Freedom
Percentiles of the
F 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
•
•
Summary of ANOVA table obtained from SAS software
Interactions identified as significant are highlighted
Alcoa Power and Propulsion
Ultimate Strength – 17-4PH
17-4PH - Ultimate Tensile Strength (UTS)
176
KSI
174
172
170
168
166
A1
A2
B1
B2
C1
C2
Strain Rate / Crosshead Speed
Factor
Degree of Freedom
Percentiles of the
F 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 Propulsion
0.2% Offset Yield Strength – 17-4PH
17-4PH - 0.2% Offset Yield Strength
135
KSI
133
131
129
127
125
A1
A2
B1
B2
C1
C2
Strain Rate / Crosshead Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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 Propulsion
Percent Elongation – 17-4PH
17-4PH - Elongation
Percent
13.0
12.5
12.0
11.5
A1
A2
B1
B2
C1
C2
Strain Rate / Crosshead Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Percent Reduction of Area – 17-4PH
17-4PH - Reduction of Area
65
Percent
64
63
62
61
60
A1
A2
B1
B2
C1
C2
Strain Rate / Crosshead Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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 Propulsion
Ultimate Strength – CMSX-4 ®
CMSX-4® - UTS
175
KSI
165
155
145
135
125
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
0.2% Offset Yield Strength – CMSX-4 ®
CMSX-4® - 0.2% Yield Strength
150
145
KSI
140
135
130
125
120
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Elongation – CMSX-4 ®
CMSX-4® - Elongation
25
Percent
20
15
10
5
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Reduction of Area – CMSX-4 ®
CMSX-4® - Reduction of Area
25
Percent
20
15
10
5
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Ultimate Strength – Cast Alloy 718
Cast Alloy 718 - UTS
175
KSI
170
165
160
155
150
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
0.2% Offset Yield Strength – Cast Alloy 718
Cast Alloy 718 - 0.2% Yield Strength
150
148
KSI
146
144
142
140
138
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Elongation – Cast Alloy 718
Cast Alloy 718 - Elongation
12
Percent
10
8
6
4
2
0
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Reduction of Area – Cast Alloy 718
Cast Alloy 718 - Reduction of Area
25
Percent
20
15
10
5
0
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Ultimate Strength – Wrought Alloy 718
KSI
Wrought Alloy 718 - UTS
211
210
209
208
207
206
205
204
203
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
0.2% Offset Yield Strength – Wrought Alloy 718
Wrought Alloy 718 - 0.2% Yield Strength
180
178
KSI
176
174
172
170
168
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Elongation – Wrought Alloy 718
Wrought Alloy 718 - Elongation
21.0
Percent
20.0
19.0
18.0
17.0
16.0
A1
A2
B1
C1
B2
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
Conclusion
Strain
2
F(0.95,2,12) = 3.89
0.16
0.16 ≤ 3.89
Crosshead
1
F(0.95,1,12) = 4.75
373.48
373.48 > 4.75
Strain * Crosshead
2
F(0.95,2,12) = 3.89
1.11
1.11 ≤ 3.89
Result
Not Significant
Significant
Not Significant
Alcoa Power and Propulsion
Reduction of Area – Wrought Alloy 718
Wrought Alloy 718 - Reduction of Area
41.5
Percent
41.0
40.5
40.0
39.5
39.0
38.5
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F 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
Alcoa Power and Propulsion
Ultimate Strength – Stellite 31®
Stellite 31® - UTS
140
135
KSI
130
125
120
115
110
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
0.2% Offset Yield Strength – Stellite 31®
Stellite 31® - 0.2% Yield Strengh
95
KSI
90
85
80
75
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Elongation – Stellite 31®
Stellite 31® - Elongation
11
10
Percent
9
8
7
6
5
4
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Reduction of Area – Stellite 31®
Stellite 31® - Reduction of Area
14
Percent
12
10
8
6
4
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Ultimate Strength – Ti-6-4
Ti-6-4 - UTS
146
144
KSI
142
140
138
136
134
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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 Propulsion
0.2% Offset Yield Strength – Ti-6-4
Ti-6-4 - 0.2% Yield Strength
132
130
KSI
128
126
124
122
120
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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
Alcoa Power and Propulsion
Elongation – Ti-6-4
Ti-6-4 - Elongation
18
Percent
16
14
12
10
8
6
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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 Propulsion
Reduction of Area – Ti-6-4
Ti-6-4 - Reduction of Area
36
Percent
31
26
21
16
11
6
A1
A2
B1
B2
C1
C2
Strain Rate / Cross Head Speed
Factor
Degree of Freedom
Percentiles of the
F distribution
F*
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 Propulsion
ANOVA Summary for Significant Relationships
17-4PH
Strain
Crosshead
Strain*Crosshead
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 Propulsion
Variation in Time to Fracture
Time in Minutes
Time to Fracture
8
7
6
5
4
3
2
1
0
17-4PH
CMSX-4®
Alloy 718 - Cast
Alloy 718 - Wrought
Stellite 31®
Ti-6-4
A1
A2
B1
B2
C1
C2
Strain Rate / Crosshead Speed
Alcoa 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 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
Alcoa Power and Propulsion