Interaction between γ'precipitate distribution and microstructure homogeneity during hot deformation in a Ni-based superalloy
作者机构：Beijing Key Laboratory of Advanced High Temperature MaterialsCentral Iron&Steel Research InstituteBeijing100081China Beijing GAONA Materials&Technology Co.Ltd.Beijing100081China
出 版 物：《Journal of Iron and Steel Research(International)》 (钢铁研究学报（英文版）)
年 卷 期：2023年第30卷第11期
页 面：2301-2317页
核心收录：
学科分类：08[工学] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学]
基 金：supported by the National Key R&D Program of China(No.2017YFA0700703) the National Natural Science Foundation of China(No.52074092).
主 题：GH4730 alloy Hot deformation γ′phase Heterogeneous factor Microstructure homogeneity
摘 要：The inhomogeneous microstructure of the Ni-based superalloys used for turbine disks was an intolerable defect for the mechanical performance.The effects of the distribution ofγ precipitate,forging temperature,and strain level on the microstructure evolution of GH4730 alloy were investigated by EBSD during hot deformation.The results showed that the heterogeneous factor peaked at the transition temperature from the single-phase to the double-phase region.The coupling effect of heat and stress led to the heterogeneous precipitation and distribution ofγ phase during the transition region,which was the main reason for the formation of inhomogeneous microstructures.The coherentγ phases of approximately 0.3μm were diffusely distributed inside the large grains,increasing the grain strength,making recrystallization refinement difficult,and thus forming large unrecrystallized grains.The incoherentγ phases with a size of approximately 1.1μm located at the grain boundaries and pinned the grain boundaries,and thus the accumulated strain at the grain boundaries caused the occurrence of discontinuous dynamic recrystallization and promoted continuous refinement of the grains.The microstructure evolution of new Ni-based superalloys during hot forging was focused,and the formation mechanism of inhomogeneous microstructure and control measures was explained.A theoretical basis for improving the microstructure homogeneity of the new cast and wrought superalloys was provided.
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