球磨时间对粉末冶金制备超细晶Mg-3Al-Zn合金组织及力学性能的影响  

Effect of ball milling time on microstructure and mechanical properties of ultrafine-grained Mg-3Al-Zn alloy prepared by powder metallurgy

作　　者：房娃[1] 李继光 杜正勇 FANG Wa;LI Ji-guang;DU Zheng-yong(National-Local Joint Engineering Laboratory of Intelligent Manufacturing Oriented Automobile Die&Mold,Tianjin University of Technology and Education,Tianjin 300222,China;Tianjin Long March Launch Vehicle Manufacturing Co.,Ltd.,Tianjin 300462,China)

机构地区：[1]天津职业技术师范大学汽车模具智能制造技术国家地方联合工程实验室,天津300222 [2]天津航天长征火箭制造有限公司,天津300462

出　　处：《材料工程》2020年第12期119-125,共7页Journal of Materials Engineering

基　　金：国家自然科学基金项目(51875409)。

摘　　要：采用高能球磨+冷压制坯+温挤压工艺制备超细晶Mg-3Al-Zn合金,研究球磨时间对合金组织及力学性能的影响。结果表明:球磨过程中Al和Zn元素完全固溶到镁基体中,形成了单相固溶体。球磨20 h后,粉末颗粒平均粒径约为25μm,平均晶粒尺寸约为45 nm;粉末经冷压制坯+温挤压致密化后,球磨20 h合金的平均晶粒尺寸为600 nm,晶粒形状规则且为等轴晶。所有超细晶合金都表现出较高的力学性能,球磨20 h后合金屈服强度为369 MPa,抗拉强度为401 MPa,断裂应变为3.5%。超细晶镁合金的拉伸真应力-真应变曲线呈现出一种理想刚塑性的特征,而压缩真应力-真应变曲线明显分为加工硬化、加工软化、加工硬化3个阶段。The ultrafine-grained Mg-3Al-Zn alloy was prepared by high energy ball milling,cold vacuum press and warm extrusion.The influence of ball milling time on the microstructure and mechanical properties of the alloy was studied.The results show that Al and Zn elements completely dissolve into the magnesium matrix in the process of ball milling.The single phase solid solution is formed.After the ball-milling for 20 h,the average particle size of the powder particles is about 25μm,and the average grain size is about 45 nm.After the powder is densified by cold pressing and warm extruded,the average grain size of the alloy milled for 20 h is 600 nm,and the grain shape is regular and equiaxed crystal.All ultrafine-grained alloys show higher mechanical properties.The yield strength,tensile strength and breaking strain of the alloy after ball milling for 20 h are 369 MPa,401 MPa and 3.5%,respectively.The tensile true stress-true strain curve of ultrafine-grained magnesium alloy shows a characteristic of ideal rigid plasticity.The compression true stress-true strain curve can be divided into three stages:working hardening,working softening and working hardening.

关 键 词：超细晶 镁合金 微观组织 力学性能 球磨时间 

分 类 号：TG146.22[一般工业技术—材料科学与工程]