挤压AZ31B镁合金板材高温轧制变形行为研究  

Deformation behavior of extrude AZ31B Mg alloy sheets during high temperature rolling

作　　者：魏松波[1] 蔡庆伍[1] 唐荻[1] 胡水平[1] 孟强[1] 

机构地区：[1]北京科技大学高效轧制国家工程研究中心,北京100083

出　　处：《塑性工程学报》2009年第1期95-101,共7页Journal of Plasticity Engineering

基　　金：国家"十一五"科技支撑计划重点项目"镁及镁合金关键技术开发与应用"子课题"变形镁合金板材加工技术研究"(2006BAE04B02)

摘　　要：通过单道次轧制试验,研究了AZ31B挤压镁合金板材在温度为365℃和450℃时的轧制性能,其变形量范围为10%～60%,应变速率为2.1s-1～5.0s-1。通过光学显微镜和扫描电镜观察了轧制变形中的微观组织及其演变。结果表明,在变形的初始阶段,孪生为主要的变形机理和硬化机制。由孪生变形积聚的畸变能和非基滑移的启动,导致了动态再结晶的形核与长大,增大变形速率可以抑制晶粒长大,使平均晶粒尺寸细化到7μm～10μm。365℃温轧制变形使板材晶粒明显细化,温度较高时,晶粒细化作用有限。在同一变形量下,随着轧制温度的升高,板材的晶粒呈长大趋势,在365℃轧制温度下,随着道次变形量的加大,细晶百分含量随之迅速增加。当轧制温度提高到450℃时,晶粒细化有限,晶粒尺寸保持在20μm以上。The hot deformation properties of as-extruded AZ31B Mg alloy sheet are tested by single pass rolling at a temperature range of 365℃ and 450℃, under a reduction range of 10%-60% and strain rate of 2.1 to 5.0s^-1. The microstructure evolution during the rolling is observed by optical microscopy （OM） and scanning electronic microscopy （SEM） . It is demonstrated that twinning and sliding are the primary deformation mechanism and hardening mechanism at the initial stage of 365℃ rolling. The distortion energy stored by twinning and the activation of non-basal slip are responsible for the nucleation and growth of dynamic recrystallization （DRX）. As roiling rate increases, the volume of fine grains increased quickly and the average grain size decreases to 7μm-10μm. When rolling temperature increases to 450℃, the grain refining is restrained and the average grain size keeps above 20μm.

关 键 词：AZ31B镁合金 轧制 微观组织 孪生 动态再结晶 切变带 

分 类 号：TG335.5[金属学及工艺—金属压力加工]