合金元素对激光熔覆高熵合金涂层硬度影响的研究进展

激光熔覆技术采用高能量密度的激光作为工艺的能量来源,能够对工件表面进行改性和修复,显著地改善了基体的表面力学性能,从而有效地延长了产品的生命周期。激光熔覆是制备高熵合金的典型工艺之一,采用该技术并且添加合适的合金元素可以制备具备卓越性能的高熵合金涂层。为清晰地阐明加入元素后增强激光熔覆高熵合金涂层硬度的作用机制,首先综述了目前国内外在激光熔覆过程中加入常见元素所制备的高熵合金涂层硬度性能的研究现状,其中高熵合金有特殊的“4种效应”,对金属间化合物有促进作用,其内部微观结构一般为FCC、BCC或者HCP等固溶相,通常通过固溶强化、沉淀强化和分散强化来强化,并且激光熔覆法会使高熵合金涂层快速冷却,从而显著改善合金的力学性能。其次,分析了金属与非金属两大类元素对激光熔覆制备高熵合金涂层硬度强化的机理,总结了金属元素与非金属元素的添加对高熵合金涂层硬度的影响规律。最后,针对激光熔覆制备高熵合金涂层硬度性能的改进,总结出了有效的方法,并对其未来发展进行了展望。研究结果揭示了激光熔覆高熵合金涂层硬度强化的理论基础,为该领域的进一步发展提供了理论依据。

Research Progress on the Effect of Alloying Elements on the Hardness of Laser Cladded High Entropy Alloy Coatings

Laser cladding technology uses high energy density laser as the energy source of the process, which can modify and repair the surface of the workpiece, significantly improve the mechanical properties of the matrix surface, and effectively extend the life cycle of the product. Laser cladding is one of the typical processes for the preparation of high entropy alloys. By using this technology and adding appropriate alloying elements, high entropy alloy coatings with excellent properties can be prepared. In order to clearly clarify the mechanism of enhancing the hardness of laser cladded high entropy alloy coatings after addition of elements, the current research status of hardness properties of high entropy alloy coatings prepared by adding common elements in laser cladding process in China and abroad is reviewed firstly. Among them, high entropy alloy has special "four effects", which can promote intermetallic compounds. Its internal microstructure is generally FCC, BCC or HCP solid solution phase. It is usually strengthened by solution strengthening, precipitation strengthening and dispersion strengthening, and the laser cladding method allows the high entropy alloy coating to cool rapidly, thus significantly improving the mechanical properties of the alloy. Secondly, the mechanism of metal and non-metal elements on the hardness strengthening of high entropy alloy coating prepared by laser cladding is analyzed, and the effect of addition of alloy elements on the hardness of high entropy alloy coating is summarized. Finally, in order to improve the hardness properties of high entropy alloy coating prepared by laser cladding, the effective method is summarized and its future development is prospected. The research results reveal the theoretical fundamentals for strengthening the hardness of laser cladded high entropy alloy coatings, and provide a theoretical basis for the further development of this field.