The Phase Stability, Ductility and Hardness of MoN and NbN: First-Principles Study

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• 作者：Yaoyao Linghu ; Xiaozhi Wu ; Rui Wang ; Weiguo Li ; Qing Liu
• 关键词：Phase stability ; mechanical properties ; electronic structure ; first ; principles methods
• 刊名：Journal of Electronic Materials
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：46
• 期：3
• 页码：1914-1925
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Optical and Electronic Materials; Characterization and Evaluation of Materials; Electronics and Microelectronics, Instrumentation; Solid State Physics;
• 出版者：Springer US
• ISSN：1543-186X
• 卷排序：46

文摘

The phase stabilities of Mo\(_{1-x}\)Al\(_{x}\)N and Nb\(_{1-x}\)Al\(_{x}\)N \((x=0, 0.25, 0.5, 0.75, 1.0)\) with four possible WC, NiAs, B1 and B4 structures were investigated using first-principles methods. With the increase of Al contents, the most stable structure changes from WC (\(x=0\) and 0.25) to NiAs (\(x=0.5\)) structure. When \(x=0.75\) and 1.0, the most stable structure is B4. The elastic constants, Young’s modulus, shear modulus, bulk modulus and elastic anisotropy were calculated. Based on the Pugh criterion and Poisson’s ratio, the ductility and hardness of Mo\(_{1-x}\)Al\(_{x}\)N and Nb\(_{1-x}\)Al\(_{x}\)N were investigated. The ductility of Mo\(_{1-x}\)Al\(_{x}\)N decreases with the increase of Al contents. However, the ductility of Nb\(_{1-x}\)Al\(_{x}\)N enhances with the increase of Al contents. The density of states and charge density differences were used to analyze the mechanical properties. The results are in agreement with the predictions based on the Pugh criterion and Poisson’s ratio.