Effect of Interactions Among Elements on Diffusion Process Associated with γ′ Coarsening in a Ni-Based Single-Crystal Superalloy
来源期刊：Acta Metallurgica Sinica2020年第7期
论文作者：Guang-Lei Wang Dong-Qing Qi Ji-De Liu Jin-Lai Liu Yi-Zhou Zhou Xu-Dong Sun Hai-Feng Zhang Xiao-Feng Sun
文章页码：1013 - 1020
摘 要：Coarsening of cuboidal γ’ precipitates and relevant diffusion process in Ni-based single-crystal superalloy CMSX-4 were investigated at 1000,1020 and 1040℃ for specific times.The y’ coarsening kinetics followed a cubic rate law with time and was presumably controlled by bulk diffusion of elements in y matrix.The associated diffusion activation energy was experimentally determined to be about 300 kJ/mol when it is considered the temperature-dependent thermo-physical parameters in modified Lifshitz-Slyozov-Wagner theory.The influence of temperature on γ/γ’ microstructure is briefly discussed based on pseudo-binary [Ni]-[Al] phase diagram.Interactions among elements can effectively raise the local vacancy formation and vacancy-atom exchange barriers close to γ-and γ’-partitioning elements,respectively.Thus,it can significantly reduce the inter-coupling migrations of atoms during the macroscopic cross-diffusion process associated with γ’ coarsening of Ni-based superalloys.
Guang-Lei Wang1,2，Dong-Qing Qi1，Ji-De Liu2，Jin-Lai Liu2，Yi-Zhou Zhou2，Xu-Dong Sun1，Hai-Feng Zhang1,2，Xiao-Feng Sun2
1. School of Materials Science and Engineering,Northeastern University2. Superalloys Division, Institute of Metal Research,Chinese Academy of Sciences
摘 要：Coarsening of cuboidal γ’ precipitates and relevant diffusion process in Ni-based single-crystal superalloy CMSX-4 were investigated at 1000,1020 and 1040℃ for specific times.The y’ coarsening kinetics followed a cubic rate law with time and was presumably controlled by bulk diffusion of elements in y matrix.The associated diffusion activation energy was experimentally determined to be about 300 kJ/mol when it is considered the temperature-dependent thermo-physical parameters in modified Lifshitz-Slyozov-Wagner theory.The influence of temperature on γ/γ’ microstructure is briefly discussed based on pseudo-binary [Ni]-[Al] phase diagram.Interactions among elements can effectively raise the local vacancy formation and vacancy-atom exchange barriers close to γ-and γ’-partitioning elements,respectively.Thus,it can significantly reduce the inter-coupling migrations of atoms during the macroscopic cross-diffusion process associated with γ’ coarsening of Ni-based superalloys.
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