Cr对CoFeNiAl0.6Ti0.4的合金化行为与组织的影响

采用"机械合金化+SPS烧结"制备了CoFeNiAl0.6Ti0.4和CrCoFeNiAl0.6Ti0.4块体高熵合金,研究元素Cr对CoFeNiAl0.6Ti0.4高熵合金的合金化行为和组织的影响。结果表明:Cr元素并不影响CoFeNiAl0.6Ti0.4高熵合金的合金化顺序,而影响完全合金化后的晶体结构,使CoFeNiAl0.6Ti0.4高熵合金原本单一的fcc结构转变为fcc+bcc结构。SPS烧结后,CoFeNiAl0.6Ti0.4高熵合金主要为fcc+bcc主相+微量bcc白相,而Cr元素的添加促使合金转变成fcc主相+微量bcc白相。同时,合金元素Cr的加入,使CoFeNiAl0.6Ti0.4高熵合金中的微量白相,由原本富Al和Fe元素转变为富Al和Ti元素;且Cr元素不影响CoFeNiAl0.6Ti0.4高熵合金中fcc结构的纳米孪晶组织的形成。

Effect of Cr on the Alloying Behavior and Microstructure of CoFeNiAl0.6Ti0.4

In order to investigate the effect of Cr on the alloying behavior and microstructure of CoFeNiAl0.6Ti0.4 high entropy alloy, CoFeNiAl0.6Ti0.4 and CrCoFeNiAl0.6Ti0.4, were prepared by mechanical alloying (MA) and spark plasma sintering (SPS). During MA, Cr did not affect the alloying sequence. But Cr could facilitate the single fcc structured phase of CoFeNiAl0.6Ti0.4 high entropy alloy transforming into fcc+bcc structured phases after being completely alloyed. After SPS, CoFeNiAl0.6Ti0.4 high entropy alloy exhibited main fcc+bcc phases and tiny bcc phase with white contrast; however, CrCoFeNiAl0.6Ti0.4 high entropy alloy showed main fcc phase and tiny bcc phase with white contrast. Moreover, the tiny bcc phase with white contrast was Al-enriched and Fe-enriched, while Al-enriched and Ti-enriched with Cr addition. Cr had no effect on the formation of nanoscale twins with fcc structure of CoFeNiAl0.6Ti0.4 high entropy alloy.