Strain hardening mechanisms in aged AEREX350 superalloy

In this paper, results of an investigation on strain hardening mechanisms of aged AEREX350 alloy during room temperature compression testing are reported. TEM studies were conducted on commercial samples aged at 850 degrees C both before and after deformation in a strain range of 0.15-0.27. It was found that only coherent gamma' precipitates with L1(2), structure formed in these samples prior to deformation. TEM studies also showed twin intersections in the deformed samples. Based on these observations, it is suggested that the high strain hardening rate of the aged material in this strain range is mainly related to the formation of intersecting deformation twins. This is attributed to the decrease in the matrix stacking fault energy due to the precipitation of high-nickel-content gamma' phase. (c) 2005 Elsevier B.V. All rights reserved.