超塑性材料的单向拉伸均匀变形和颈缩速度的研究

A Study on Uniform Deformation and Necking Velocity of Superplastic Material under the Condition of Uniaxial Tension

均匀变形条件是超塑性材料迭到很高塑性的一个条件。文章用塑性基本理论导出幂硬化特性的在单向拉伸时均匀变形条件,它适用范围较广,幂硬化塑性材料的均匀变形条件是它的一个特例。从该均匀变形条件可以看到W.A.Backofen所提出的超塑性材料不可能有绝对意义上的均匀变形,但可以通过分析颈缩的速度和应变速率敏感性指数m来分析超塑性的高低。

When uniform deformation condition is satisfied, superplastic materials will have very high plasticity. A uniform deformation condition of the superplastic materials with a power - hardening characteristic under uniaxial tension is obtained in this paper by using basic plastic theory. It is applicable to many other situations. The uniform deformation condition of power - hardening materials is one of its special instances. From the uniform deformation condition, the conclusion is drawn that there is no uniform deformation in an absolute sense regarding the materials presented by W. A. Backofen. However, superplasticity of materials can be analyzed from necking velocity and strain rate sensitive index .