Solution heat treatment is an essential method to eliminate the solidification segregation of Ni-based single-crystal superalloys.The premise for the solution heat treatment is that there should exist a suitable solution window.With the development of the alloy,the solid solution window gradually narrows,increasing the difficulty of solution heat treatment.Since the solid solution window is dynamic,the upper limit of the initial melting temperature increases with the dissolution of the γ′phase and eutectic in the alloy.Therefore,it is of great significance to study the influence of the solution heat treatment process on the initial melting temperature.However,there is a lack of relevant research.In this paper,the effects of step and ramp solution heat treatment on microstructure and initial melting temperature was studied by transmission electron microscope.It was found that solution heat treatment promoted the homogenization behavior.The degree of homogenization increased with the prolongation of the holding time at high temperatures in the solution heat treatment process.The better homogenization effect increased the initial melting temperature,but it also promoted the Kirkendall effect and induced more solid solution micropores.
关键词
镍基单晶高温合金/固溶处理/初熔温度/微观组织
Key words
Ni-based single crystal superalloys/solution window/solution process/initial melting temperature
维普
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