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利用透射电镜研究了蠕变变形(650~750℃,250~350 MPa)Ti-47 Al-2Nb-2Mn(at%)+0.8TiB_2(vol%)合金的微观组织及变形机制。结果表明,该合金的微观组织由等轴状γ相和(γ+α_2)区域组成;在层片状γ中,观察到1/2<110]普通位错外,还发现了层错。与化学计量比TiAl化合物中的结果不同,该富Ti的TiAl合金中所观察到的{111}层错是由1/6[112]和1/6[121]位错在{111}面的运动产生的。基于对该合金中层错形成机制的认识,本文探讨了合金元素Mn和Nb等对TiAl基合金变形机制的影响。
The microstructure and deformation mechanism of Ti-47Al-2Nb-2Mn (at%) + 0.8TiB_2 (vol%) alloy under creep deformation (650-750 ℃, 250-350 MPa) were studied by transmission electron microscope. The results show that the microstructure of the alloy is composed of equiaxed γ phase and (γ + α 2) regions, and in the lamellar γ, 1/2 <110] common dislocations are observed. Unlike the results in stoichiometric TiAl compounds, the observed {111} stacking fault in Ti-rich TiAl alloys is caused by the formation of {111} planes of 1/6 [112] and 1/6 [121] Exercise generated. Based on the understanding of the mechanism of the formation of layer faults in this alloy, the effects of alloying elements such as Mn and Nb on the deformation mechanism of TiAl-based alloys were discussed.