【摘要】 研究了一种等温锻造态Ｔｉ－４７Ａｌ－１Ｃｒ－１Ｖ－１．５Ｍｏ－１．５Ｍｏ－１．５Ｎｂ（原子分数，％）合金的超塑变形行为和组织变化．结果表明：在９００℃，ε＝５×１０－４ｓ－１和大气条件下，合金的应变速率敏感性指数ｍ大于０．５，延伸率为２００％．超塑变形时，在相晶内、晶界和层状组织中发生了动态再结晶动态再结晶可松弛界面滑动造成的应力集中，也为合金进一步的超望变形创造了组织条件．晶粒中发生｛１１１｝［１１０］普通位错滑移、｛１１１｝＜１０１］超点阵位错滑移和｛１１１｝＜１１２］类型孪生变形位锗滑移和孪生既对变形做出贡献，同时也作为调节机制起作用．更多还原

【Abstract】 Superplastic behavior and microstructural evolution of an isothermal forged Ti-47Al-1Cr- 1V-1.5Mo-1.5Nb (atomic fraction,%) alloy were studied. The results show that the strain rate sensitivity m is larger than 0.5 at 900℃ 5×10-4 s-1 and air and the maximum elongation is 200%. During the su- perplastic deformation, dynamic recrystallization occurred in grains, boundaries and lamellar structures. Dynamic recrystallization released the stress concentration due to grain boundary sliding and provided the microstructural condition for further deformation. {111} <110] dislocation slip, {111} <101] superlattice dislocation slip and {111} <112] twinning took place in 7 grains. Slip and twinning acted as both deformation and accommodation mechanisms.更多还原