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采用 TEM 衍衬试验研究了 TiAl+Mn 合金中层错带和变形孪晶的特征。结果表明:所观察到的层错带是一组在平行(111)面上的重叠层错,提出这种重叠层错是由柏氏失量■=1/6[112]的不全位错扫过相继平行(111)面时形成的。分析结果还表明,按上述机制所形成的重叠层错的取向与观察到的变形孪晶一致。因此,重叠层错实际上是变形孪晶的胚胎。基于以上对层错带及变形孪晶形成过程的认识,本文进一步探讨了第三元素对 TiAl 基合金孪生变形及延性的影响。
The characteristics of interlaminar zonation and deformation twins in TiAl + Mn alloys were investigated by TEM. The results show that the observed fault zone is a set of overlapping faults on the parallel (111) plane, suggesting that this overlapping fault is swept over by an incomplete dislocation with a Bohr loss of ¼ 1/6 [112] Successively parallel (111) surface formed. The analysis also shows that the orientation of the stacking faults formed by the above mechanism is consistent with the observed deformation twinning. As a result, overlapping faults are actually embryos that deform twins. Based on the above understanding of the formation of strata and deformable twins, this paper further explores the effect of the third element on the twin deformation and ductility of TiAl-based alloys.