高级检索

Nb元素对高熵合金涂层组织与力学性能的影响

Effect of Nb components on the microstructure and mechanical properties of high-entropy alloy coatings

  • 摘要: 利用激光熔覆技术在Q235基体表面制备CoCrFeNiTi0.8Nby(y = 0.25,0.5,0.75,1.0)涂层.采用光学显微镜、X射线衍射仪、扫描电子显微镜、能谱分析仪等方法分析涂层的相结构和微观组织等;用显微维氏硬度计、摩擦磨损试验机测试涂层的硬度与耐磨性能.结果表明,组织中呈现典型的树枝晶结构,加入Nb元素,涂层微观组织的尺寸减小,增加Nb元素含量时,高熵合金涂层的晶体结构由体心立方相(body-centered cubi,BCC)、少量的面心立方相(face-centered cubic,FCC)和Fe2(Ti,Nb)型的Laves相组成;在细晶强化、固溶强化和第二相强化的共同作用下提高了涂层的显微硬度;中间相的存在一定程度上可以阻碍犁削切削过程的进行,进而提高了涂层的耐磨性能;CoCrFeNiTi0.8Nb0.75涂层的硬度和耐磨性最好,硬度为710 HV,约为基体的4倍,涂层的磨损量最小,磨痕较为平整.

     

    Abstract: CoCrFeNiTi0.8Nby (y = 0.25, 0.5, 0.75, 1.0) coatings were prepared on the surface of Q235 steel using laser cladding. The phase structure and microstructure of the coatings were analyzed by optical microscope (OM), X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The hardness and wear resistance of the coatings were tested by micro-Vickers hardness tester and friction wear tester. The results show that the microstructure shows a typical dendritic crystal structure, and the addition of Nb elements decreases the size of the grains; by increasing the content of Nb elements, the crystal structure of the high-entropy alloy coatings consists of BCC phases, a small amount of FCC phases, and Fe2(Ti, Nb)-type Laves phases; the microhardness of the coatings is improved by the combined effect of fine-grained reinforcement, solid solution strengthening, and the strengthening of the second phase; The presence of the intermediate phase can hinder the plough cutting process to a certain extent, which improves the wear resistance of the coating; CoCrFeNiTi0.8Nb0.75 coating has the best hardness and wear resistance, the hardness of 710 HV, about 4 times that of the substrate, and the coating has the smallest amount of abrasion, and the abrasion marks are relatively flat.

     

/

返回文章
返回