高纯多晶铝的动态再结晶

Dynamic Recrystallization of High Purity Polycrystalline Aluminum

将99.992%高纯多晶铝在533～773K时以0.002～2.000s-1的应变速率压缩到其真应变为0.92。采用真应力 真应变曲线以及偏光金相和透射电镜研究高纯铝高温塑性变形特征,研究了形变条件对高纯铝动态软化机制的影响。研究结果表明:高纯铝的动态软化机制与Zenner Hollomon参数Z密切相关,当Z较大时,试样仅发生动态回复;Z处于中间值时,发生连续动态再结晶;Z较小时,发生不连续动态再结晶,但真应力 真应变曲线未出现波动。

Specimens of high purity Aluminum of 99.992% grade were hot compressed to a true strain of 0.92 at 533773 K and with strain rates of 0.0022.000 s^(-1). The dynamic restoration mechanisms were examined by the true stress-true strain curves, polarized microscopy and transmission electron microscopy. The effect of parameter Z (Zener-Hollomom parameter) on the restoration mechanisms of high purity aluminum was investigated. The results show that only dynamic recovery occurs when parameter Z is high; continuous dynamic recrystallization occurs when parameter Z is intermediate, and discontinuous dynamic recrystallization takes place if parameter Z is low. But the true stress-true strain curve does not accompany stress oscillation when discontinuous dynamic recrystallization occurs.