温轧态Fe_3Al-Ti合金的低温超塑性

Superplasticity in Warm-Rolled Fe_3Al-Ti Alloy at Low Temperature

采用拉伸试验研究了温轧态 Fe3Al- Ti合金 Fe- 2 8Al- 2 Ti的低温变形行为 .发现当应变速率为 1.2 5× 10 - 4 s- 1和 2 .5× 10 - 4 s- 1时 ,该合金在 6 0 0～ 70 0℃具有超塑性 .70 0℃时断裂延伸率可达 389%,根据试验数据计算出应变速率敏感指数一般低于 0 .3.金相组织观察表明 ,变形过程中发生了动态回复和动态再结晶 ,从而导致了温轧态 Fe3Al- Ti合金的超塑性 .

Low temperature deformation behavior of warm- rolled Fe- 2 8Al- 2 Ti alloy was investigated by tensile tests.This alloy shows superplasticity in 6 0 0～ 70 0℃ under strain rates of 1.2 5× 10 - 4 s- 1and 2 .5× 10 - 4 s- 1.The tensile elongation increases with the temperature from 6 0 0～ 70 0℃ and the maximum is up to 389%at70 0℃ .Strain- rate sensitivity( m value) is below0 .3.The fracture surface observations indicate that the fracture mode of this alloy varies from a mixture of transgranular cleavage and intergranular frac- ture to ductile fracture in 6 0 0～ 70 0℃ .Our optical micrographs reveal that dynamic recovery and recrystal- lization take place during the tensile deformation process,which lead to the superplasticity in warm- rolled Fe- 2 8Al- 2 Ti alloy.