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在750℃下对近片层Ti--45Al--8Nb--0.2W--0.2B--0.1Y合金进行了静拉伸和循环变形,观察和分析变形后试样的微观组织.合金在750℃时的循环应力--应变曲线位于静拉伸应力--应变曲线之上,显示出明显的循环硬化特征;在循环变形过程中呈现先硬化后稳定.透射电镜观察显示,在750℃下循环变形和拉伸的合金试样中均发现有大量的位错钉扎、塞积及缠结存在,而形变孪晶仅在循环变形后的合金试样中存在.合金在750℃下的循环变形中孪生起重要作用.
The tensile and cyclic deformation of the Ti - 45Al - 8Nb - 0.2W - 0.2B - 0.1Y alloy near the sheet was investigated at 750 ℃ and the microstructure of the deformed sample was observed and analyzed. The cyclic stress-strain curve at 750 ℃ is located above the static tensile stress-strain curve and shows obvious characteristics of cyclic hardening. In the cyclic deformation process, it shows first hardening and then stabilizing. Transmission electron microscopy shows that at 750 ℃ A large amount of dislocation pinning, plugging and entanglement were found in the alloy specimens deformed and stretched, while the deformation twins were only found in the alloy specimens after cyclic deformation. The cycle of the alloy at 750 ℃ Twins play an important role in deformation.