等通道转角挤压Mg-3.52Sn-3.32Al合金的组织与力学性能

采用等通道转角挤压（ECAP）Bc路径对固溶态Mg-3.52Sn-3.32Al合金分别挤压1、4和8道次。利用光学显微镜、扫描电子显微镜、透射电子显微镜和X射线衍射仪分析合金的组织和相组成，并测试了其室温拉伸力学性能。结果表明，经ECAP挤压后，固溶态合金组织中析出大量细小的Mg2Sn相和极少量的Mg17Al12相。随挤压道次增加，合金的综合力学性能先提高后降低。经4道次挤压后，合金的综合拉伸力学性能相对较佳，抗拉强度、伸长率和硬度分别达到250 MPa、20.5%和61.3 HV9.8，较未ECAP时分别提高43.7%、105%和26.9%。经ECAP挤压的合金室温拉伸断口均呈韧性断裂。等通道转角挤压Mg-3.52Sn-3.32Al合金的力学性能受晶粒尺寸、析出相以及组织织构的共同影响。

Microstructure and tensile properties of solutionized Mg-3.52Sn-3.32Al alloy deformed by equal channel angular pressing

The solutionized Mg-3.52Sn-3.32Al(wt.%) alloy was processed by equal channel angular pressing (ECAP) via route Bc for 1, 4, and 8 passes, respectively. The microstructure and phase composition of the alloy were analyzed by optical microscope, scanning electron microscopy, transmission electron microscopy and X-ray diffraction, and the room-temperature mechanical properties were measured. The results show that many fine Mg2Sn particles and a few Mg17Al12 phases precipitate in the alloy after ECAP. The mechanical properties of the alloy first increase and then decrease gradually with increasing extrusion passes. The alloy possesses better mechanical properties after ECAP for four passes, the ultimate tensile strength, elongation and hardness increase to 250 MPa, 20.5% and 61.3 HV9.8 respectively, which is increased by 43.7%, 105% and 26.9% compared with the solutionized alloy. The room temperature fractograph of the ECAP processed alloy is ductile-fractured morphology under tensile condition.The mechanical properties of the ECAP processed Mg alloy is dependent on the grain size, precipitate and texture.