激光熔覆Co1.5CrFeNi1.5Ti0.75Nbx高熵合金的组织和性能研究

目的 研究Nb含量对高熵合金Co1.5CrFeNi1.5Ti0.75Nbx熔覆层组织和性能的影响.方法 在H13钢表面制备了Co1.5CrFeNi1.5Ti0.75Nbx(x=0.25,0.50,0.75,1.00,原子数分数)高熵合金熔覆层,研究Nb含量对熔覆层的物相组织、微观结构、硬度和耐磨性的影响.结果 高熵合金熔覆层主要为BCC相、FCC相和Laves相的组织.在熔覆层中添加Nb,Laves相随之增加,组织的微观形貌发生变化.熔覆层的硬度远远高于H13钢(退火态),Co1.5CrFeNi1.5Ti0.75Nb0.5熔覆层的平均硬度最高,约为H13钢(退火态)的2.8倍.Co1.5CrFeNi1.5Ti0.75Nb0.5熔覆层的摩擦磨损失重最小,磨损程度更低,耐磨性更好.结论 Nb元素加入高熵合金体系会形成Laves相,Laves相能够提高高熵合金的力学性能.相关结果 对于高熵合金体系的研究具有一定意义,为高熵合金的成分设计和优化提供了必要的实验支持.

Microstructure and Properties of Laser Cladding Co1.5CrFeNi1.5Ti0.75Nbx High-Entropy Alloy

The work aims to study the effect of Nb content on the structure and properties of the high-entropy alloy Co1.5CrFeNi1.5Ti0.75Nbx cladding layer. The Co1.5CrFeNi1.5Ti0.75Nbx (x=0.25, 0.50, 0.75, 1.00) high-entropy alloy cladding layer was prepared on the surface of H13 steel, and the influence of Nb content on the phase structure, microstructure, hardness and abrasive resistance of the cladding layer was studied. The high-entropy alloy cladding layer was mainly composed of BCC phase, FCC phase and Laves phase. When Nb was added to the cladding layer, the Laves phase increased, and the microstructure of the structure changed. The hardness of the cladding layer was much higher than that of H13 steel (annealed), and the average hardness of the Co1.5CrFeNi1.5Ti0.75Nb0.5 cladding layer was the highest, which was about 2.8 times that of H13 steel (annealed). The Co1.5CrFeNi1.5Ti0.75Nb0.5 cladding layer had the smallest friction and wear loss, lower wear degree and better wear resistance. The addition of Nb element to the high-entropy alloy system will form the Laves phase, which can improve the mechanical properties of the high-entropy alloy. The relevant results have certain significance for the study of high-entropy alloy systems, and provide necessary experimental support for the composition design and optimization of high-entropy alloys.