热挤压工艺对Mg-4Li-1Al合金组织与性能的影响  

Influences of Hot Extrusion Process on Microstructure and Properties of Mg-4Li-1Al Alloy

作　　者：袁雷[1] 沙桂英[1] 宋猛[1] 岳子健 李志常[1] 

机构地区：[1]沈阳航空航天大学材料科学与工程学院,辽宁沈阳110136

出　　处：《热加工工艺》2015年第11期68-70,共3页Hot Working Technology

摘　　要：通过对Mg-4Li-1Al合金进行热挤压和拉伸实验,以及显微组织分析和微观断口分析,研究了挤压工艺对合金显微组织和力学性能及微观断裂机制的影响。结果表明:采用挤压温度为200℃、挤压比为3.9、挤压速度为30mm/min的工艺热挤压后,合金中存在大量的孪晶,α-Mg晶粒沿挤压方向变形明显;当挤压温度升高至270℃、挤压比增大至9.7,合金显微组织中的孪晶基本消失,且α-Mg晶粒产生了局部的动态再结晶。随着挤压温度升高、挤压比增大,Mg-4Li-1Al合金的塑性大幅度提高,伸长率提高约2.5倍,断面收缩率提高约2.1倍。同时,合金的断裂方式由以解理断裂和沿晶断裂为主的混合断裂转变为准解理断裂。The effects of hot extrusion technology on the microstructure, mechanical properties and fracture mechanism of the Mg-4Li-1Al alloy were investigated by the hot extrusion and tensile tests, along with the microstructure and fracture morphology analysis. The results show that a lot of twin exists in the alloy after hot extrusion at 200℃,extrusion ratio of 3.9and extrusion speed of 30 mm/min, and α-Mg grains are extended obviously along the extrusion direction. When the extrusion temperature rises to 270℃ and extrusion ratio increases to 9.7, the twins in the microstructure of the alloy disappear basically,and α-Mg grains in the alloy come into being partially dynamic recrystallization. With the extrusion temperature raising and extrusion ratio increasing,the plasticity of the Mg-4Li-1Al alloy improves significantly, elongation ratio increases by about 2.5 times, and reduction ratio of area increases by about 2.1 times. Meanwhile, the fracture mode of the alloy changes from mixed fracture dominated by cleavage and intergranular fracture to quasi-cleavage fracture.

关 键 词：MG-LI-AL合金 热挤压 显微组织 力学性能 断裂机制 

分 类 号：TG376.2[金属学及工艺—金属压力加工]