【摘要】 引入了一个衡量超塑性拉伸断面收缩均匀性的特征参数λ,在假设变形以扩散为主的条件下,导出了λ的表达式。令λ=0时,得到断面均匀收缩的临界应变速率ε觶cri。ε觶cri与扩散系数和应变量成正比,与试样原始截面积成反比。对AZ31镁合金超塑性拉伸特征参数λ值的测定结果表明:当应变速率越接近于临界应变速率,λ越小,试样越接近均匀变形。更多还原

【Abstract】 A parameter named λ was put forward and an equation was deduced to characterize the uniform deformation of superplastic tensile test under the conditions of diffusion dominated deformation.By solving the equation at λ=0,a critical strain rate εcri of uniform deformation was got ten.The results show that εcri is direct proportion to strain and diffusion coefficient and inversely proportion to the cross section area of undeformed specimens.The results of the tested λ of AZ31 alloy under superplastic tensile show that λ is becoming significant small and the cross section of the specimen tends to be uniform deformation when strain rate is near εcri.更多还原