Micromechanism in fracture toughness of NbCr2 laves phase improved by nickel alloying: first-principles calculation
Micromechanism in fracture toughness of NbCr2 laves phase improved by nickel alloying: first-principles calculation
复制标题
DOI：
10.1016/j.jallcom.2020.158040
复制
发表时间：
2020-12
影响因子：
6.2
通讯作者：
Hai-long Huang;Guifa Li;Xuan Xiao;Shi-qiang Lu;P. Peng
中科院分区：
文献类型：
--
作者：
Hai-long Huang;Guifa Li;Xuan Xiao;Shi-qiang Lu;P. Peng
基于第一性原理计算，通过结合能、断裂韧性、电子结构等参数对镍合金化改良NbCr2Laves相断裂韧性的微观机制进行了评价。形成焓和结合能结果表明Nb8Cr16−xNix相可以稳定形成。然而，当Ni含量仅为4.17 at%（Nb8Cr15Ni）时，其在（100）、（110）和（111）方向的断裂韧性值KIC仅能得到明显提高。 Mulliken布居分析表明，Nb8Cr15Ni相在三个主要米勒指数方向上的RLBOP（局部键重叠布居比）值比NbCr2Laves相更接近1，这意味着Nb8Cr15Ni相的力学性能表现出更好的韧性。电子结构表现出其最佳断裂韧性主要来自于(110)米勒指数方向金属键的强化和共价键的减弱。因此，我们的研究结果为 NbCr2Laves 材料的综合研究开辟了潜在的途径。
Based on the first-principle calculation, the micromechanism in fracture toughness of the NbCr2Laves phase improved by Nickel alloying was estimated by several parameters such as binding energy, fracture toughness, electronic structure, et al. The results of formation enthalpy and binding energy show that the Nb8Cr16−xNixphase can be formed stably. However, when the Ni content is only 4.17 at% (Nb8Cr15Ni), its fracture toughness valueKICin (100), (110) and (111) directions can be only improved obviously. Mulliken population analysis shows that theRLBOP(ratio of local bond overlap population) values of Nb8Cr15Ni phase in three main Miller index directions are much closer to 1 than that of the NbCr2Laves phase, which means the mechanical performance of Nb8Cr15Ni exhibits much better toughness. The electronic structure shows its optimal fracture toughness mainly comes from the strengthening of metal bonds and the weakening of covalent bonds in the direction of (110) Miller index. Thus our findings open a potential avenue for the comprehensive study of NbCr2Laves materials.