Abstract Boride-based cermets possess attractive mechanical properties and are promising candidates for hard materials. Mo2NiB2–Ni-based cermet, which is a boride-based cermet, exhibits high hardness and attractive transverse rupture strength (TRS) properties through the crystal structure deformation that is caused by Cr or V substitution of Ni in the Mo2NiB2 phase. In this study, the effects of Cr substitution on the crystal structure, mechanical properties, and consistency were investigated. Cr-substituted Mo2Ni1-xCrxB2 samples were synthesized via the powder metallurgy method. A first-principle calculation was also conducted to obtain the bulk modulus of the Cr-substituted Mo2Ni1-xCrxB2. With the increase of the Cr content x, the tetragonal-Mo2NiB2 phase appeared, while the orthorhombic Mo2NiB2 phase disappeared. In the x = 0.6 samples, the Mo2Ni0.4Cr0.6B2, tet-Mo2NiB2 phase was observed. According to the Rietveld analysis, substituted Cr atoms occupied the Ni and Mo sites in the tet-Mo2NiB2 structure. The Rockwell A-scale hardness (HRA) measurement was performed to investigate the effects of the Cr content on the mechanical properties. The HRA values increased with the Cr content, and the maximum HRA value was approximately 87.1 for the x = 0.6 sample. The bulk modulus was also affected by the Cr content x in Mo2Ni1-xCrxB2, and the maximum value was attained at x = 0.75.

中文翻译：

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Mo2Ni1-Cr B2硬质材料的合成及晶体结构

摘要 硼化物基金属陶瓷具有吸引人的机械性能，是硬质材料的有前途的候选材料。Mo2NiB2–Ni 基金属陶瓷是一种硼化物基金属陶瓷，通过在 Mo2NiB2 相中由 Cr 或 V 取代 Ni 引起的晶体结构变形，表现出高硬度和有吸引力的横向断裂强度 (TRS) 性能。在这项研究中，研究了 Cr 取代对晶体结构、机械性能和一致性的影响。Cr 取代的 Mo2Ni1-xCrxB2 样品是通过粉末冶金方法合成的。还进行了第一性原理计算以获得 Cr 取代的 Mo2Ni1-xCrxB2 的体积模量。随着Cr含量x的增加，四方-Mo2NiB2相出现，而正交Mo2NiB2相消失。在 x = 0.6 个样本中，观察到 Mo2Ni0.4Cr0.6B2，tet-Mo2NiB2 相。根据 Rietveld 分析，取代的 Cr 原子占据了 tet-Mo2NiB2 结构中的 Ni 和 Mo 位点。进行洛氏 A 级硬度 (HRA) 测量以研究 Cr 含量对机械性能的影响。HRA 值随着 Cr 含量的增加而增加，对于 x = 0.6 的样品，最大 HRA 值约为 87.1。体积模量也受 Mo2Ni1-xCrxB2 中 Cr 含量 x 的影响，在 x = 0.75 时达到最大值。HRA 值随着 Cr 含量的增加而增加，对于 x = 0.6 的样品，最大 HRA 值约为 87.1。体积模量也受 Mo2Ni1-xCrxB2 中 Cr 含量 x 的影响，在 x = 0.75 时达到最大值。HRA 值随着 Cr 含量的增加而增加，对于 x = 0.6 的样品，最大 HRA 值约为 87.1。体积模量也受 Mo2Ni1-xCrxB2 中 Cr 含量 x 的影响，在 x = 0.75 时达到最大值。