GH5188高温合金组织特征及冷热加工过程组织演变

Microstructure Characteristics and Microstructure Evolution during Hot and Cold Working Process of GH5188 Superalloy

为了给控制生产工艺、优化产品性能提供理论参考,利用SEM、EDS和Thermo-Calc热力学软件研究了GH5188钴基高温合金生产加工过程中的组织演变及热处理工艺。结果表明:GH5188合金主要相组成为γ相、M_6C和M_(23)C_6,采用1200℃/20 h的均匀化制度可明显消除铸态组织偏析;热轧态组织晶粒细小且有大量碳化物沿着轧向平行析出;冷轧态组织晶粒扭曲变形严重,颗粒状M_6C为主要析出相。当退火温度高于1170℃时,晶界处的二次碳化物基本回溶,再结晶晶粒能够正常长大。

In order to provide theoretical guidance for production process control and products performance optimization, the microstructure evolution and heat treatment in the production process of GH5188 cobalt-base superalloy were investigated by SEM, EDS and Thermo-Calc software. The result indicates that the main phases of GH5188 alloy include γ, M6_C and M_（23）C_6. The 1200 °C/20 h homogenization could reduce segregation of as-cast microstructure. Hot-rolled microstructure has a fine grain size, and a large number of aligned carbides precipitating along the rolling direction. In the cold-rolled microstructure with serious grain deformation, granular M6_C is found to be the predominant phase. When the annealing temperature is higher than 1170 °C, secondary carbides at the grain boundaries dissolve back into γ and recrystallized grain can grow in normal way.