变形温度对2A14铝合金显微组织和力学性能的影响  

Effects of deformation temperature on microstructure and mechanical properties of 2A14 aluminum alloy

作　　者：刘文胜[1] 刘东亮[1] 马运柱[1] 王娟[1] 杨波平[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《中国有色金属学报》2015年第2期308-314,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家高新技术研究发展计划资助项目(2009AA034300);教育部"长江学者特聘教授"奖励计划

摘　　要：在300-450℃温度范围内对2A14铝合金进行恒应变速率的多向压缩实验，模拟其多向锻造过程，采用金相显微镜（OM）、扫描电镜（SEM）、透射电镜（TEM）和室温力学性能测试等手段研究变形温度对2A14合金的显微组织和力学性能的影响。结果表明：随着变形温度的升高，合金的软化机制由动态回复向动态再结晶转变，位错密度随之降低；变形后的2A14铝合金在热处理过程中，发生静态再结晶，变形过程中累积的形变储能对再结晶的形核及长大具有促进作用。随着变形温度的升高，时效态2A14铝合金的平均晶粒尺寸随之增大，分布变得不均匀，其强度与平均晶粒尺寸满足Hall-Petch关系式；室温拉伸断口形貌表现出韧性断裂特征，且随着变形温度的升高，单位面积内韧窝数量减少、尺寸增大，合金的靼性变差。The multi-axial compression tests of 2A14 aluminum alloy were carried out with a constant strain rate to simulate the multi-forging process in the temperature range from 300 to 450 ℃. The effects of hot deformation temperature on microstructure and mechanical properties of 2A14 aluminum alloy were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy and mechanical property testing. The results show that, with the increase of the deforming temperature, the dislocation density decreases, and the softening behavior of the alloy transforms from dynamic recovery to dynamic recrystallization. The compressed samples have stored high deformation energy, which can supply driving force for nucleation and grain growth of static recrystallization during heat-treatment. With the increase of the deformation temperature, the average grain size of the aged alloy increases and presents uneven distribution, meanwhile, the relationship between the strength and average grain size meets the Hall-Petch equation. The microstructure of the fracture is consisted of a large number of equiaxed dimples, and with the increase of the deforming temperature, the number of dimples decreases while the size of dimples increases which indicates a toughness fracture mode during tensile testing.

关 键 词：2A14铝合金 变形温度 显微组织 力学性能 多向压缩 

分 类 号：TG146.2[一般工业技术—材料科学与工程]