摘要
本文研究了L1_0型TiAl和TiAl+Mn金属间化合物的室温力学特性和变形亚结构。实验结果表明:添加合金元素Mn可以促进TiAl合金中的孪生变形,从而使其室温延性得以明显改善。建立了TiAl有序结构中孪生变形的位错模型,根据该模型,阐述了TiAl合金的孪生过程及其晶体学特征,重点讨论了合金元素Mn对TiAl合金孪生变形影响的机制,指出了超位错可动性增强和层错能降低是促进孪生变形的两个重要因素。
The mechanical behaviour and deformation substructure of TiAl binary andTiAl+Mn ternary intermetallic compounds of L1_0 type at room temperatureare studied. The results indicate that Mn-addition can enhance twinning defor-mation and thus improve room-temperature ductility of TiAl alloys remarkab-ly. A dislocation model for twinning deformation in TiAl ordered structureis proposed, based on which the crystallographic features of deformation twinsand the twinning processes are explained. The emphasis is placed on the mecha-nism of the effects of Mn-addition on the twinning deformation in TiAl alloys.It is pointed out that the enhancement of twinning in TiAl by Mn-addition iscaused by the enhanced movement of superdislocations and the decrease of stac-king fault energy.
基金
本研究得到了国家八六三计划和国家教委优秀年轻教师基金
