【摘要】 由于超塑性材料具有非常高的伸长率,可以成形形状复杂的精密零件。本文针对超塑成形的基本理论进行了探讨,推导出超塑性厚向异性板气压胀形成形压力与成形时间的计算公式,讨论了在不同厚向异性系数时,成形压力和成形时间与长径比h之间的变化规律。计算结果表明:(1)当压力恒定时,等效应变率是h的变量;当等效应变率为常量时,压力就是h的变量;(2)厚向异性系数r越大,成形时间就越长,所需要的压力也越大;(3)不论r值多大,无量纲压力都在h=0.9处有一个极值。更多还原

【Abstract】 Sophisticated machine parts can be formed because of high elongation of superplastic materials.Forming pressure and forming time of superplastic free bulging of normal anisotropic plate under air pressure were derived.Variations of forming pressure and forming time vs.the ratio of length to diameter h were discussed under different coefficients of normal anisotropy.The results show that:(1)When the pressure remains constant,equivalent strain rate will vary with h;when the equivalent strain rate remains constant,forming pressure will vary with h;(2)The larger coefficient of normal anisotropy r is,the longer forming time is and the larger required pressure is;(3)No matter how much r values is,the dimensionless pressure has an extreme value at h=0.9.更多还原