Alcoa Power and Propulsion Effect of Testing Speed on Several Alloys Susan Morford Alcoa Howmet Research Center

Alcoa 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 Propulsion Design of Experiment Test Conditions (Full-factorial – all combinations were tested) –Strain rates A – inch/inch/minute B – inch/inch/minute C – 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 AlloyBase AlloyAlloy TypeSpecimen Configuration 17-4PHIronCastMachined CMSX-4 ®NickelCastMachined Alloy 718Nickel/IronCastCast to Size Alloy 718Nickel/IronWroughtMachined Stellite 31®CobaltCastCast to Size Ti-6-4TitaniumCastCast to Size

Alcoa Power and Propulsion Analysis Methodology - Graphical Center Line: Mean of three (3) SpecimensSpread: ± 1 Standard Deviation

Alcoa Power and Propulsion Analysis Methodology - ANOVA Summary of ANOVA table obtained from SAS software Interactions identified as significant are highlighted Factor Degree of FreedomPercentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = > 4.75Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Ultimate Strength – 17-4PH Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = > 4.75Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion 0.2% Offset Yield Strength – 17-4PH Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = > 3.89Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Percent Elongation – 17-4PH Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Percent Reduction of Area – 17-4PH Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = > 3.89Significant

Alcoa Power and Propulsion Ultimate Strength – CMSX-4 ® Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion 0.2% Offset Yield Strength – CMSX-4 ® Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Elongation – CMSX-4 ® Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Reduction of Area – CMSX-4 ® Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = > 3.89Significant

Alcoa Power and Propulsion Ultimate Strength – Cast Alloy 718 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = > 4.75Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion 0.2% Offset Yield Strength – Cast Alloy 718 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Elongation – Cast Alloy 718 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Reduction of Area – Cast Alloy 718 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Ultimate Strength – Wrought Alloy 718 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion 0.2% Offset Yield Strength – Wrought Alloy 718 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Elongation – Wrought Alloy 718 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = > 4.75Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Reduction of Area – Wrought Alloy 718 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = > 4.75Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Ultimate Strength – Stellite 31® Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion 0.2% Offset Yield Strength – Stellite 31® Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Elongation – Stellite 31® Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Reduction of Area – Stellite 31® Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Ultimate Strength – Ti-6-4 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = > 4.75Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion 0.2% Offset Yield Strength – Ti-6-4 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = > 3.89Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Elongation – Ti-6-4 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = Not Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion Reduction of Area – Ti-6-4 Factor Degree of Freedom Percentiles of the F distribution F*ConclusionResult Strain2F(0.95,2,12) = Not Significant Crosshead1F(0.95,1,12) = > 4.75Significant Strain * Crosshead2F(0.95,2,12) = Not Significant

Alcoa Power and Propulsion ANOVA Summary for Significant Relationships StrainCrossheadStrain*Crosshead 17-4PH0.2% YSUTSROA CMSX-4®ROA Alloy CastUTS Alloy Wrought % Elongation, ROA Stellite 31 ® Ti % YSUTS, ROA

Alcoa Power and Propulsion Variation in Time to Fracture

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 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 ± /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