给出了能精确表达Zn Al2 2 % ,Al Zn Mg和Al Zn Cu Cr比较典型的 3种超塑性合金的lgσ lg ε关系的多项式 .进而用m(ε·)和k( ε)的解析表达式求得m和k均为变数的似粘性流变方程 ,方程中包含了与m lg ε曲线相关的 3个参数mm ,mk和 η ,并且指出 ,mm,η ,mm/mk 越大 ,合金的超塑性越好 ,而且Backofen方程只是变参数本构方程的一个特例 . The polynomials of lgσ lg ε, which can express accurately Zn Al 2 2%, Al Zn Mg and Al Zn Cu Cr, are given. And then the expressions of m (ε ·) and k (ε) M and k are variable viscosity like rheological equations, the equation contains m lg ε curve related to the three parameters mm, mk and η, and pointed out that mm, η, mm / mk the greater the alloy The better the superplasticity, and the Backofen equation is just a special case of the constitutive equation of variable parameters.