B2结构的铝-镝金属间化合物位错性质的研究

Study on {110} plane dislocation core structure and Peierls stress of B2 aldy

摘要:

本文用截断近似法,研究了B2结构的铝-镝金属间化合物{110}面的位错性质。结果表明,伯格斯矢量为<110>方向的螺位错、刃位错和混合位错的芯宽度都要比<100>方向窄。它们相应的的不稳定层错能存在γ_us<110>大于γ_us<001>的关系,可见,不稳定层错能是影响具有B2结构的金属间化合物位错性质的重要因素之一。B2-AlDy滑移系为<111>{110}的位错,除了位错角为54.7°的位错以外,其他位错角的弹性应变能都要大于失配能,而且在相同周期内看,它们的相位总是相反；位错角为54.7°的位错,失配能比弹性应变能大,而且两者在相同周期内同相位。总体来说,B2-AlDy的{110}面上<100>、<110>和<111>方向的位错,随着位错角的减小(<111>方向的54.7°的位错除外),总能量以及相应的应力都依次增大。

关键词:AlDy;不稳定层错能;位错芯结构;Peierls应力

Abstract:

Dislocation properties of {110} in Al-Dy intermetallic compound with B2 structure were studied by truncation approximation.The results show that the Burgess vector is <110>, the core width of the directional screw, edge and mixed dislocation should be greater than <100> irection. Their corresponding unstable stratification energy is present γ_us<110> < γ_us<001>. It can be seen that the unstable stratification energy is one of the important factors affecting the dislocation properties of intermetallic compounds with B2 structure. B2-AlDy slip system is <111>. For the dislocation of {110}, except for the dislocation with a dislocation Angle of 54.7°, the elastic strain energy of other dislocation angles is greater than the misfit energy, and their phases are always opposite in the same period.When the dislocation Angle is 54.7°, the misfit energy is greater than the elastic strain energy, and both of them are in phase in the same period. In general, for the {110} plane of B2-AlDy, <100>, <110> and <111> direction of dislocation, with the reduction of dislocation angle (except the <111> direction for the dislocation angle of 54.7°), the total energy and the corresponding stress increase in turn.

Key words:AlDy; unstable stacking fault energy; dislocation core structure; Peierls stress.