摘要
镁合金具有密排六方结构,可动滑移系少导致其室温塑性差,而热加工对调控镁合金塑性有重要作用。本工作对AZ80镁合金分别进行恒温、阶梯降温多道次压缩变形,利用电子背散射衍射(EBSD)技术观察分析了不同变形程度、不同变形路径下AZ80镁合金的微观组织,研究了AZ80镁合金热压缩变形过程中晶界、位错密度、Schmid因子和极图演化规律。结果表明:晶粒尺寸、孪晶、织构综合作用对AZ80镁合金塑性调控的影响优于单一动态再结晶对其塑性调控的影响,恒温三次变形(ε=0.6)(3P)有利于发生动态再结晶,而阶梯降温三次变形(ε=0.6)(3P)更有利于塑性变形。晶粒取向差减小、小角度晶界(LAGBs)数量增多、几何必需位错(GND)密度增加3者共同作用产生更多86°{1012}<1210>拉伸孪晶是影响阶梯降温三次变形塑性调控的重要因素。
Magnesium alloy has a hexagonal close-packed crystal structure,and its plasticity is poor at room temperature.This is primarily due to the small number of movable slip systems at room temperature,which is prone to deformation texture.Therefore,temperature and compression deformation play an important role in the regulation of plastic deformation.In this work,AZ80 magnesium alloy was subjected to multi-pass compression deformation at a constant temperature and step-down temperature.The microstructure of the AZ80 magnesium alloy with different deformation degrees and deformation paths was observed and analyzed using EBSD.In addition,the grain boundary,dislocation density,Schmid factor,and polar figure evolution of the AZ80 magnesium alloy during hot compression deformation were primarily studied.Results show that the comprehensive effect of grain size,twinning,and texture on the plastic regulation of AZ80 magnesium alloy is better than that of single dynamic recrystallization.Moreover,threetime constant-temperature deformation(ε=0.6)promotes dynamic recrystallization,whereas three-time step-cooling deformation(ε=0.6)promotes plastic deformation.More 86°{1012}<1210>tensile twins are produced by reduced grain orientation difference,increased number of low-angle grain boundaries,and increased geometrically necessary dislocation density,which are important factors affecting the plastic regulation of three-time step-cooling deformation(ε=0.6).
作者
李振亮
张欣磊
田董扩
LI Zhenliang;ZHANG Xinlei;TIAN Dongkuo(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第3期311-322,共12页
Acta Metallurgica Sinica
基金
国家自然科学基金项目No.51364032
内蒙古自然科学基金项目No.2022MS05028。
关键词
AZ80
晶界
取向差
几何必需位错密度
塑性调控
AZ80
grain boundary
misorientation
geometrically necessary dislocation density
plastic regulation
