Dynamic Strain Aging of Nickel-Base Alloys 800H and 690

The objective of the current investigation is to characterize the dynamic strain aging (DSA) behavior in alloys 800H and 690. Constant extension rate tests were conducted at strain rates in the range of 10(-4) s(-1) to 10(-7) s(-1)and temperatures between 295 K and 673 K (22 A degrees C and 400 A degrees C), in an argon atmosphere. Maps for the occurrence of serrated flow as a function of strain rate and temperature were built for both alloys. The enthalpy of serrated flow appearance of alloy 800H was found to be 1.07 +/- A 0.30 eV.