L12型Al3(Sc1-xZrx)力学性质的第一原理研究
首发时间:2017-03-20
摘要:为研究L12型Al3(Sc1-xZrx)合金的力学性质,采用密度泛函理论和虚拟晶体近似方法计算了晶体结构、弹性性质(B,G,Y),并利用Cauchy压力(C12-C44)与Pugh准则(B/G值)表征不同含量Zr(0<x<0.5)对Al3(Sc1-xZrx)韧脆性的影响。结果表明:随着Zr元素含量的增加,L12型Al3(Sc1-xZrx)晶体的晶格常数减小,体模量B增大,而剪切模量G和杨氏模量Y都减小;Zr元素含量的增加改善了晶体的延展性;通过分析电子态密度发现,Zr对L12型Al3(Sc1-xZrx)韧性的强化作用主要源于增加的价电子数,从而增强晶体内金属键和共价键的作用。
关键词: 计算固体力学 Al-Sc-Zr合金 虚拟晶体近似 弹性性质 电子结构
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Study of first principles in the mechanical properties of L12-Al3(Sc1-xZrx) alloys
Abstract:To investigate the mechanical properties of L12-Al3(Sc1-xZrx) compounds, first principles calculations with virtual crystal approximation are performed by calculating the structure and elastic properties (B, G, Y). The ductility of the crystal is predicted by the Pugh empirical criterion (B/G) and Cauchy pressure (C12-C44). The calculated results suggest that the increased content of Zr in L12-Al3(Sc1-xZrx) has diminished the optimized structural parameters, Shear modulus and Young’s modulus, while enlarged bulk modulus. The ductility of L12-Al3(Sc1-xZrx) is improved with the added Zr. The electronic density of states reveal that, the valence electron is increasing with added Zr content, which resulting in the strengthen of the metallic bonding and covalent bonding, and benefiting the improvement of the mechanical properties and ductility.
Keywords: computational solid mechanics Al-Sc-Zr alloys virtual crystal approximation elastic properties electronic structures
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