B2结构的铝-镝金属间化合物位错性质的研究

Dislocation Properties of B2-Al Dy Intermetallics Compound

采用截断近似法,研究了B2结构的铝-镝(B2-Al Dy)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。它们相应的不稳定层错能存在γus<110>大于γus<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-Al Dy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-Al Dy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°的位错角除外),总能量以及相应的应力都依次增大。

Dislocation properties of{110}in B2-structure Al Dy intermetallic compound were studied by truncation approximation.The results show that when the Burgess vector is<110>,the core width of the screw,edge and mixed dislocation should be smaller than that of<100>direction.Their corresponding unstable stacking fault energy has the relationship thatγus<110>is greater thanγus<001>.It can be seen that the unstable stacking fault energy is one of the important factors affecting the dislocation properties of intermetallic compounds with B2 structure.The slip system of B2-Al Dy is<111>{110};except for the dislocation with a dislocation angle of 54.7°,all 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 have the same phase when in the same period.In general,for the<100>,<110>and<111>dislocation on{110}plane of B2-Al Dy,with the reduction of dislocation angle(except for the 54.7°dislocation angle of<111>direction),the total energy and the corresponding stress increase in turn.