Microstructure and properties of as-cast and annealed Al0.5CoCrFeNiTi0.5 high-entropy alloys

被引：0
作者：
Jiang S.-Y. [1 ]
Lin Z.-F. [1 ]
Xu H.-M. [1 ]
机构：
[1] College of Mechanical and Electronic Engineering, China University of Petroleum (Huadong), Qingdao
来源：
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | 2019年 / 29卷 / 02期
关键词：
Annealing; Corrosion resistance; High-entropy alloy; Mechanical property; Microstructure;
D O I：
10.19476/j.ysxb.1004.0609.2019.02.14
中图分类号：
学科分类号：
摘要：
Al0.5CoCrFeNiTi0.5 high entropy alloys were prepared by vacuum arc melting and were treated by vacuum annealing at 600, 800 and 1000℃ for 10 h. The microstructure, mechanical properties and corrosion resistance in the 3.5% NaCl solution of the as-cast and annealed alloys were studied by XRD, OM, EPMA, hardness tester, universal testing machine, and electrochemical workstation. The microstructure analysis shows that the as-cast and three kinds of annealed alloys are all composed of FCC rich (Cr, Fe), BCC rich (Al, Ni, Ti) and σ, but their microstructure morphologies and the relative contents of each phase are different. As the annealing process, the thick white FCC columnar crystals in the as-cast alloy shift to the mixed structures of FCC, BCC and σ, and with the increase of annealing temperature, the contents of the BCC and σ phase increase. The 800℃-annealed alloy has the best composition uniformity, and the 1000℃-annealed alloy has the increasing element segregation and the coarse microstructure due to the high annealing temperature. The hardness and compression tests show that all of the as-cast and three kinds of annealed alloys have high hardness, showing good resistance to tempering softening, the 800℃-annealed alloy has the highest hardness and yield strength but its plasticity is the worst due to the increase of the BCC and σ phase content, the yield strength, fracture strength and compressive deformation rate of the 1000℃-annealed alloy sharply decrease due to its coarse structure and a large number of σ precipitation, the 600℃-annealed alloy has the best comprehensive mechanical properties due to the ideal contents of FCC, BCC and σ. The electrochemical corrosion tests show that the as-cast and three kinds of annealed alloys all have good corrosion resistance in 3.5% NaCl solution and the corrosion resistance of the 800℃-annealed alloy is the best because of its best composition uniformity. © 2019, Science Press. All right reserved.
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页码：326 / 333
页数：7
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