Experiments show that the magnesium AZ31 (Mg-3 pet Al-1 pet Zn) alloy exhibits excellent superplastic properties at 623 K (350 °C) after processing by equal-channel angular pressing using a die with a channel angle of 135 deg and a range of decreasing processing temperatures from 473 K to 413 K (200 °C to 140 °C). A maximum elongation to failure of -1200 pct was achieved in this alloy at a tensile strain rate of 1.0 x 10~(-4) s~(-1). Microstructural inspection showed evidence for cavity formation and grain growth during tensile testing with the grain growth leading to significant strain hardening. An examination of the experimental data shows that grain boundary sliding is dominant during superplastic flow. Furthermore, a comprehensive review of the present results and extensive published data for the AZ31 alloy shows the exponent of the inverse grain size is given by p ≈ 2 which is consistent with grain boundary sliding as the rate-controlling flow mechanism.
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机译：实验表明，镁等离子AZ31（Mg-3 pet Al-1 pet Zn）合金在使用135度通道角的模具进行等通道角压加工后，在623 K（350°C）下表现出优异的超塑性。降低的加工温度范围为473 K至413 K（200°C至140°C）。在1.0 x 10〜（-4）s〜（-1）的拉伸应变率下，该合金的最大破坏伸长率为-1200 pct。显微组织检查显示出在拉伸测试过程中空穴形成和晶粒长大的证据，晶粒长大导致明显的应变硬化。对实验数据的检查表明，在超塑性流动期间晶界滑动是主要的。此外，对当前结果的全面回顾和有关AZ31合金的大量公开数据表明，反向晶粒尺寸的指数由p≈2给出，这与作为速率控制流动机制的晶界滑动相一致。
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