Al-Li-Cu-Mg-Zr合金的超塑性研究

A STUDY ON SUPERPLASTICITY OF Al-Li-Cu-Mg-Zr ALLOY

Al-1.91Li-1.25Cu-0.46Mg-0.21Zr合金超塑性变形结果表明,最佳的时效工艺是400℃8h;冷轧工艺得到了比温轧(550％)更高的超塑性延伸率(630％);最佳超塑性变形工艺是T=500℃,(?)_i=3.33×10^(-3)s^(-1)(起始拉伸速度)。研究指出,Al-1.91Li-1.25Cu-0.46Mg-0.21Zr合金的超塑性预处理的时效工艺和轧制工艺影响了合金超塑变形初期的应变诱发再结晶,从而影响超塑性性能。超塑变形中的动态回变和动态再结晶是晶界滑动的重要协调机制之一。

The superplastic deformation results of Al-l.91Li-l.25Cu-0.46Mg-0.21Zr alloy show that the optimum aging process is 400'C , 8h; cold rolled specimens display higher elongation (5 = 630%) than hot rolled ones do (δ5 = 550%); the optimum condition of superplastic deformation is T=550℃ , εi =3.33 × 10 -3s-1 (initial strain rate). It is found out by TEM (transmission electron microscope) observations and grain boundary angle measuring that under the optimum deformation condition, dynamic recovery and dynamic recrystallization are present in the total process of superplastic deformation of Al-l.9Li-l.25Cu-0.46Mg -0.21Zr alloy, which is close to an eguilibrium. Grain boundary angle measuring results also indicate that the superplastic pre-processes of Al-I.91Li-l.25Cu-0.46Mg-0.21Zr alloy affect the grain boundary structure of the alloy. It is pointed out that the superplastic pre-processes of Al-l.91Li-l.25Cu-0.46Mg-0.21Zr alloy (aging process and rolling process) affect the strain-induced-recrystallization at early stage of superplastic deformation and superplastic properties, and dynamic recovery and dynamic recrystallization are one of the important accomodation mechanisms for grain boundary sliding in superplastic deformation.