新型含Cu高熵合金的微观组织及热处理过程相变

Microstructure and Phase Transition during Heat Treatment of a New Cu Rich High-Entropy Alloy

目的为优化CrMnFeCoNi高熵合金成分,消除富Cr脆性相的析出倾向。方法用Cu取代Cr元素,以四元MnFeNiCu高熵合金为研究对象,探究含Cu高熵合金的微观组织及其热处理过程中的相变特征。结果铸态MnFeNiCu合金中Cu元素具有较强的偏析倾向,其枝晶间存在大量颗粒状富Cu析出物,通过均匀化热处理能完全消除Cu元素偏析现象,得到单相FCC组织。结论 Cu与其他3种元素均表现为不同程度的不相容性,具有最大的偏析倾向,使其在凝固过程中于枝晶间富集,均匀化热处理过程中Cu元素发生溶质扩散,最终形成了单相固溶体组织。

The work aims to optimize the composition of high entropy CrMnFeCoNi alloy and eliminate the precipitate tendency of Cr-rich phase. Cr was replaced by Cu. The microstructure and phase transformation characteristics of Cu rich high entropy alloy containing were investigated with Quaternary MnFeNiCu high entropy alloy as the research object. The Cu element in as-cast MnFeNiCu alloy had strong segregation tendency. A lot of Cu-rich precipitates existed in the interdendrite. Homogenization heat treatment can eliminate the segregation of Cu element, and get the single FCC phase. Cu shows different degrees of incompatibility with the other three elements, and has the greatest tendency of segregation, so that it is enriched in the interdendrite during solidification. Solute diffusion occurs in the homogenization heat treatment, finally forming the singlephase solid solution structure.