ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 31    No. 3    March 2021

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Effects of annealing at 800 and 1000 °C on phase precipitates and hardness of Al7Cr20FexNi73-x alloys
Chang-jun WU1,2, Chen ZHOU1, Jiao-feng ZENG1, Ya LIU1,2, Hao TU1,2, Xu-ping SU1,2
(1. Jiangsu Key Laboratory of Materials Surface Science and Technology, School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China;
2. Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University, Changzhou 213164, China
)
Abstract: The effects of Fe content on the microstructure, phase constituents and microhardness of the as-cast, 800 °C- or 1000 °C-annealed Al7Cr20FexNi73-x (x=13-66) alloys were investigated. Not all these alloys are composed of the single FCC phase. The BCC and B2 phases are found. It is confirmed that the BCC phase in the Al7Cr20Fe66Ni7 alloy is transformed from the FCC phase at about 900 °C during cooling. While in the 800 °C-annealed Al7Cr20Fe60Ni13 alloy, the FCC phase is stable and the hardness decreases. After annealing at 1000 °C, for the precipitation of the B2 particles, the Al content in the FCC phase decreases, which results in decreasing of the alloy hardness. Moreover, after annealing at 800 °C, a small amount of Al-rich B2 particles precipitate at the phase boundary and some nanocrystal BCC phase precipitates in the FCC matrix, which increases the hardness of the Al7Cr20FexNi73-x (x=41-49) alloys. These results will help to the composition design and processing design of the Al-Cr-Fe-Ni based high-entropy alloys.
Key words: high-entropy alloy; Al-Cr-Fe-Ni; phase constituent; microhardness; heat treatment
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
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