Effect of Zr, Hf, and Sn Additives on Elastic Properties of α2-Ti3Al Phase by First-principles Calculations
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2017年第4期
论文作者：张超彦 侯华 ZHAO Yuhong YANG Xiaomin HAN Peide
文章页码：944 - 950
摘 要：First-principles calculations within density functional theory have been carried out to investigate α2 phase in the Ti3Al based alloy with Zr, Hf, and Sn（6.25at%） elements doped. The lattice constants, total energies and elastic constants were calculated for the supercells. The formation enthalpies, bulk modulus, shear modulus, Young’s modulus, and intrinsic hardness were investigated. The ductility of the doped α2 phases was analyzed by the Cauchy pressure, G/B and Poisson’s ratio. The results show that the substitution of Ti（6 h） by Zr, Hf, and the substitution of Al（2n） by Sn can make the doped α2 phase more stable. The inflexibility and hardness of α2 phase can be enhanced by doping with Zr and Hf, while Sn brings the opposite effect. Sn is more powerful to improve the ductility of the doped α2 phase than Hf, but Zr can increase the brittleness. The densities of states（DOS and PDOS） and the difference charge density are obtained to reveal the underlying mechanism of the effect of alloying elements.
张超彦1，侯华1，ZHAO Yuhong1，YANG Xiaomin1，HAN Peide2
1. College of Materials Science and Engineering, North University of China2. College of Materials Science and Engineering, Taiyuan University of Technology
摘 要：First-principles calculations within density functional theory have been carried out to investigate α2 phase in the Ti3Al based alloy with Zr, Hf, and Sn（6.25at%） elements doped. The lattice constants, total energies and elastic constants were calculated for the supercells. The formation enthalpies, bulk modulus, shear modulus, Young’s modulus, and intrinsic hardness were investigated. The ductility of the doped α2 phases was analyzed by the Cauchy pressure, G/B and Poisson’s ratio. The results show that the substitution of Ti（6 h） by Zr, Hf, and the substitution of Al（2n） by Sn can make the doped α2 phase more stable. The inflexibility and hardness of α2 phase can be enhanced by doping with Zr and Hf, while Sn brings the opposite effect. Sn is more powerful to improve the ductility of the doped α2 phase than Hf, but Zr can increase the brittleness. The densities of states（DOS and PDOS） and the difference charge density are obtained to reveal the underlying mechanism of the effect of alloying elements.
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