Phase separation of metastable CoCrFeNi high entropy alloy at intermediate temperatures

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• 作者：Feng He^a ; Zhijun Wang^a ; ^{zhjwang@nwpu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Qingfeng Wu^a ; Junjie Li^a ; Jincheng Wang^a ; ^{jchwang@nwpu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; C.T. Liu^b
• 关键词：Phase separation ; High entropy alloys ; Annealing
• 刊名：Scripta Materialia
• 出版年：2017
• 出版时间：1 January 2017
• 年：2017
• 卷：126
• 期：Complete
• 页码：15-19
• 全文大小：2320 K

文摘

CoCrFeNi alloy is an exemplary stable base for high entropy alloys (HEAs), but its phase stability is still suspicious. Here, the CoCrFeNi HEA was firstly identified to be thermally metastable at 750 °C. Composition decomposition occurred after annealed at 750 °C for 800 h. The minor addition of Al accelerated the composition decomposition and a second fcc phase with a different lattice constant occurred in the long time annealed CoCrFeNiAl_0.1 HEA. The CoCrFeNi HEA cannot be seen as stable alloys anymore and researchers should be very careful when using the current phase selection models to predict stability of HEAs at intermediate temperatures.