等通道转角挤压双相Mg-10.73Li-4.49Al-0.52Y合金的组织与力学性能  

Microstructure and mechanical properties of two-phase Mg-10.73Li-4.49Al-0.52Y alloy processed by ECAP

作　　者：孔晶[1,2] 刘秦[1,2] 康志新[1,2] 

机构地区：[1]华南理工大学机械与汽车工程学院,广州510640 [2]华南理工大学国家金属材料近净成形工程技术研究中心,广州510640

出　　处：《中国有色金属学报》2012年第9期2415-2423,共9页The Chinese Journal of Nonferrous Metals

基　　金：广州市科技支撑计划项目(2009Z2-D811)

摘　　要：采用等通道转角挤压（ECAP）工艺在573K温度下以Bc路径对双相合金Mg-10．73Li-4．49A1-0．52Y进行1-6道次挤压变形，对变形合金进行显微组织观察、扫描电镜分析、x射线衍射测试和应变速率为1．5×10^-3 S^-1的室温拉伸实验。结果表明：该合金由（α＋β）相组成，变形后晶粒沿着与挤压方向成30°-45°角且呈拉长的流线状，随挤压道次的增加，晶粒不断细化，其析出相A12Y颗粒也随道次的增加沿晶粒拉长的方向均匀化和细化。合金原始铸态无织构，1道次变形后β相的主滑移面{110}晶面织构强度最高，变形3道次和6道次后该晶面织构强度相对1道次的下降，织构向周围移动。变形到3道次，室温下抗拉强度从铸态的137．5MPa提高到最大值166．4MPa；4道次后，强度有一定程度下降。断口分析表明，经6道次变形后断口呈典型的延性断裂特征，存在更多的韧窝，并获得较大的室温伸长率（83％）。The microstructure evolution and mechanical properties of Mg-10.73Li-4.49A1-0.52Y two-phase magnesium alloy processed by equal channel angular pressing （ECAP） from 1 pass to 6 passes at 573 K using route Bc were analyzed by OM, SEM and XRD, and the mechanical properties were tested at room temperature with strain rate of 1.5 X 10-3 s-1. The results indicate that the magnesium alloy grains consist of a phase and fl phase which are elongated to be streamline at an angle of 30°-45° to the extrusion direction after ECAP, and the initial large and disperse phases of Al2Y are termed and homogenized as the extrusion pass increases. After 1 pass, non-oriented texture of the as-cast alloy exhibits the strongest texture on the main crystal { 110} ofβ phase; after 3 and 6 passes, the texture intensity declines compared with that of 1 pass deformation, and their texture moves to periphery. After 3 passes, the tensile strength increases to the maximum of 166.4 MPa from 137.5 MPa of the as-cast at room temperature. After 4 passes, the tensile strength decreases a little. The fracture surfaces show that the fracture mode of the 6-pass ECAPed alloy shows typical ductile fracture and more dimples, and its elongation is up to 83%.

关 键 词：镁锂合金 等通道转角挤压 显微组织 力学性能 织构 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG376.2[金属学及工艺—金属材料]