Effects of Laser Surface Remelting on Microstructure and Properties of CoCrFeNiW0.5 High-entropy Alloy
Non-equiatomic CoCrFeNiW0.5 high entropy alloy(HEA)was prepared by vacuum arc melting followed by laser remelting treatment,the effects of laser remelting on the phase composition,microstructure,hardness and friction and wear properties of the alloy were systematically studied.The results show that the microstructure of as-cast HEA consists of dendritic FCC and interdendritic(FCC+μ)phase.After laser remelting,the eutectic structure of the alloy disappears and the grains are obviously refined,the intermetallic compound μ phase is distributed in the grain boundary of equiaxed FCC in granular form.Compared with the as-cast HEA,The remelted HEA exhibits an increase of about 17%in microhardness,a decrease of about 7%in friction coefficient and decrease of about 75%in wear rate,which is mainly due to the microstructure refinement strengthening,solid solution strengthening,and the improvement of the uniformity of the alloy microstructure and composition caused by the laser remelting process.
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