扫描电镜定量研究Zn-5%Al-0.05%Mg合金的超塑变形机制

Quantitative Study on Superplastic Deformation Mechanism in a Znc-base Alloy by SEM

用扫描电子显微术研究了微细晶粒的Zn-5%Al-0.05%Mg合金在290℃时于lgσ-igε图中的Ⅱ区或Ⅲ区内拉伸后界面滑动、晶内滑移和扩散蠕变对试样总应变量的分别贡献,获得结果如下:(1)在超塑变形的Ⅱ区内以初始应变速率1.1×10^(-3)S^(-1)拉伸到伸长14%的试样,ε_(bs)/ε_t、ε_(slip)/ε_t和ε_(dIff)/ε_t分别为72.5%、19.8%和7.7%;(2)在非超塑变形的Ⅲ区内以初始应变速率1.1×10^(-1)S^(-1)拉伸到伸长25%的试样,ε_(bs)/ε_t、ε_(slip)/ε_t、和ε_(diff)/ε_t分别为35.8%、48%和16.2%,(3)Zn/Zn晶界的滑动量大于Zn/Al相界的滑动量。

By means of SEM, the contributions of grain boundary sliding, slip and diffusion creep tothe total specimen elongation of a fine grained Zn-5% Al 0.05% Mg alloy deformed at 290℃in Region Ⅱ or Ⅲ on the lgσ--lgε phot have been investigated. The results obtained are as follows: (1)For the specimen deformed in Region Ⅱ with ε=1.1×10^(-3)s^(-1) to an elongation of 14%, ε_(b?)/ε_t,ε_(slip)/ε_?, and ε_(diff)/ε_t, are 72.5%, 19.8% and 7.7% respectively. (2) For the specimen deformedin Region Ⅲ with ε_o=1.1×10^(-1)s^(-1) to an elongation of 25%, ε_(bs)/ε_t, ε_(slip)/ε_? and ε_(biff)/ε_t, are 35.8%,48% and 16.2% respectively. (3) Sliding at Zn/Zn grain boundariesis is larger than sliding at Zn/Alinterphase boundaries.