不同形变温度下Mg-Al-Ca-Mn合金的变形机制  

Deformation mechanism of Mg-Al-Ca-Mn alloy at different deformation temperatures

作　　者：肖震东 刘宇坤 国宏伟 闫炳基 丁汉林 朱国辉 XIAO Zhen-dong;LIU Yu-kun;GUO Hong-wei;YAN Bing-ji;DING Han-lin;ZHU Guo-hui(School of Iron and Steel,Soochow University,Suzhou 215137,China;School of Metallurgical Engineering,Anhui University of Technology,Ma'anshan 243002,China)

机构地区：[1]苏州大学沙钢钢铁学院,江苏苏州215137 [2]安徽工业大学冶金工程学院,安徽马鞍山243002

出　　处：《塑性工程学报》2019年第5期174-179,共6页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51204003)

摘　　要：熔炼配制了Mg-Al-Ca-Mn合金,采用单轴拉伸实验测试了合金在25~475℃温度范围内的应力-应变曲线,通过数据处理分析了其加工硬化率曲线,并采用显微组织观察研究了不同形变温度下合金的形变机制。研究表明,合金拉伸的应力-应变曲线在不同温度下存在明显区别,且取决于其形变机制的不同。室温变形的形变机制以孪生为主,应力随应变增加而快速增加至最大值后断裂,塑性较差。425℃高温变形时主要形变机制为动态再结晶,应力在变形初期的极小应变范围内迅速达到最大值,由于动态再结晶的软化作用,应力值缓慢减小,表现出良好的变形能力。而当形变温度处于中温区(225℃)时,加工硬化阶段以孪生变形为主,随着应变的不断增加,部分区域发生动态再结晶,应力增加至最大值后缓慢减小,直到断裂。Mg-Al-Ca-Mn alloy was melted and prepared,the stress-strain curves of the alloy were obtained by the uniaxial tensile tests at temperature range of 25-475 ℃,and the hardening rate curves of the alloy were analyzed based on data processing. The microstructures observation was conducted to discuss the deformation mechanisms of the alloy at different deformation temperatures. The research indicates that there is a clear distinction of the stress-strain curves at different deformation temperatures,and the difference of the stress-strain curves attributes to the different deformation mechanisms. At room temperature,twinning is the primary mechanism to a maximum value until fracture,thus the plasticity is poor. At a high temperature of 425 ℃,the main deformation mechanism is dynamic recrystallization,and the stress reaches a maximum value at the initial stage of deformation. The flow softening of dynamic recrystallization leads to the decrease of stress with the increasing strain,resulting in excellent plasticity. While the samples deformed at middle temperature( 225 ℃),the hardening stage is dominated by twinning deformation,with the increase of strain,dynamic recrystallization occurs at some areas,the stress increases to the maximum value and then decreases slightly until the fracture.

关 键 词：Mg-Al-Ca-Mn合金 应力-应变曲线 变形机制 加工硬化率 孪晶 动态再结晶 

分 类 号：TG142.41[一般工业技术—材料科学与工程]