摘要
As-cast Mg-6Zn-xCu-0.6Zr(x=0,0.5,1.0,wt.%)alloys were fabricated by permanent mold casting;then,the alloys were subjected to homogenization heat treatment and extrusion-shearing(ES)process.The microstructure and mechanical properties of the alloys were evaluated by OM,SEM/EDS,XRD,TEM,EBSD and tensile tests.The results show that the hard MgZnCu phase in Cu-added alloy can strengthen particle-stimulated nucleation(PSN)effect and hinder the migration of dynamic recrystallization(DRX)grain boundary at an elevated temperature during ES.The ZK60+0.5Cu alloy shows an optimal tensile strength–ductility combination(UTS of 396 MPa,YS of 313 MPa,andδ=20.3%)owing to strong grain boundary strengthening and improvement of Schmid factor for{0001}■basal slip.The aggregation of microvoids around the MgZnCu phase mainly accounts for the lower tensile elongation of ZK60+1.0Cu alloy compared with ZK60 alloy.
采用金属型铸造方法制备Mg-6Zn-xCu-0.6Zr(x=0,0.5,1.0)(质量分数,%)合金,并对其进行均匀化热处理与挤压剪切成形。采用OM、SEM/EDS、XRD、TEM、EBSD及拉伸试验研究合金的显微组织及力学性能。结果表明:在挤压剪切过程中,硬质相MgZnCu能够增强粒子激发形核(PSN)效应及阻碍高温下动态再结晶(DRX)晶界的迁移。挤压剪切ZK60+0.5Cu合金具有最优的强度-塑性组合(抗拉强度396 MPa、屈服强度313 MPa和伸长率20.3%),这归因于强烈的晶界强化及{0001}■基面Schmid因子的提高。相比于ZK60合金,ZK60+1.0Cu合金伸长率的降低与MgZnCu相引起的微孔聚集有关。
基金
Project(XLYC1807021)supported by Liaoning Revitalization Talents Program,China
Project(2019JH3/30100014)supported by Joint Research Fund of Lianning-Shenyang National Laboratory for Materials Science,China
Project supported by Liaoning Bai Qian Wan Talents Program,China
Project(RC200414)supported by Innovation Talent Program in Sciences and Technologies for Young and Middle-aged Scientists of Shenyang City,China
Project(XLYC1908006)supported by High Level Innovation Team of Liaoning Province,China。
作者简介
Corresponding author:王峰,Tel:+86-15002424621,E-mail:wf9709@126.com。
