Aging process design based on the morphological evolution of γ' precipitates in a 4th generation nickel-based single crystal superalloy

In order to meet the design requirements of the aging treatment process of a 4th generation nickel-based single crystal superalloy (Ni-SX) developed independently, the effects of aging temperatures and aging times on the precipitation and morphological evolution of gamma' precipitates are studied. The morphologi-cal evolution behavior of gamma' precipitates during the aging process is summarized subsequently and the coarsening behavior of gamma' precipitates is discussed by comparing with the Lifshitz-Slyozov-Wagner model (LSW) and the trans-interface diffusion-controlled model (TIDC). It is demonstrated that primary aging temperature and secondary aging time dominate the size and squareness of gamma' precipitates respectively, a narrow primary aging temperature range and a suitable secondary aging time are allowed to obtain the optimized morphology of gamma' precipitates. The optimal aging process of the Ni-SX investigated in the present work is obtained for 1100-1120 degrees C/4 h and 870 degrees C/16 h, confirmed by the corresponding creep tests. The coarsening growth of gamma' precipitates in short-term aging also conforms to the LSW model well. Besides, the aging process design rules of various Ni-SXs of different generations are also summarized.(c) 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

This study investigates the effects of aging temperatures and aging times on the precipitation and morphological evolution of γ' precipitates in a 4th generation nickel-based single crystal superalloy (Ni-SX). The results show that the primary aging temperature and secondary aging time dominate the size and squareness of γ' precipitates respectively. The optimized aging process of Ni-SX is determined to be 1100-1120°C/4 h and 870°C/16 h.