新型反对称弧形非对称挤压对镁合金薄板微观组织和力学性能的影响  

Effect of new antisymmetric arc asymmetric extrusion on microstructure and mechanical properties of magnesium alloy sheet

作　　者：李舜 赵玲玉 LI Shun;ZHAO Lingyu(School of Mechanical Engineering,Yangzhou University,Yangzhou 225127,China)

机构地区：[1]扬州大学机械工程学院,江苏扬州225127

出　　处：《扬州大学学报（自然科学版）》2024年第4期65-71,共7页Journal of Yangzhou University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51901202)。

摘　　要：设计传统对称挤压和新型反对称弧形非对称挤压工艺制备镁合金薄板,沿薄板挤压方向倾斜0°、45°和90°取样得到挤压方向、45°和横向试样,开展室温单轴拉伸试验,评估薄板力学性能。应用电子背散射衍射技术对不同处理状态的镁合金板材进行微观组织表征,探讨晶粒尺寸及其取向分布与板材力学性能之间的关系。结果表明:与商用热轧态板材相比,传统挤压板材在挤压方向、45°和横向3个方向上的抗拉强度和延伸率均有所提高,延伸率由热轧板材的7.8%~10.1%增至传统挤压板材的18.7%~22.5%;新型非对称挤压板材在3个方向上的屈服强度、抗拉强度和延伸率均有所提高,屈服强度超过179 MPa,抗拉强度接近或超过300 MPa,延伸率13.6%~20.3%。性能的改善一方面和挤压导致的晶粒细化有关,晶粒尺寸由热轧态的24.82μm细化至传统挤压板材的10.14μm和新型非对称挤压板材的6.55μm;另一方面和挤压引起的织构弱化有关,尤其是新型非对称挤压板材因为引入法向和横向的应变梯度,基面织构显著弱化。The traditional symmetric extrusion(SE)and the new antisymmetric arc asymmetric extrusion(ACAE)processes are designed to prepare magnesium alloy sheets.Uniaxial tensile tests are carried out at room temperature to evaluate the mechanical properties of the sheets by sampling along the extrusion direction(ED)of the sheet at 0°,45°,and 90°(transverse direction,TD).Electron back scattering diffraction(EBSD)technique is used to characterize the microstructure of magnesium alloy sheets in different processing states,the relationship between grain size and its orientation distribution and the mechanical properties of the sheet is discussed.The results show that compared with the commercial hot rolled sheet,the tensile strength(UTS)and elongation(EL)of SE sheet in ED,TD and 45°directions are improved,and the EL increases from 7.8%~10.1%of hot rolled sheets to 18.7%~22.5%of SE sheets.The yield strength(YS),tensile strength and elongation of ACAE sheet in all three directions have been improved,the yield strength is more than 179 MPa,the tensile strength is close to or more than 300 MPa,and elongation is 13.6%~20.3%.On the one hand,the improvement of properties is related to the grain refinement caused by extrusion.The grain size is refined from 24.82μm in the HR sheet to 10.14μm in the SE sheet and 6.55μm in the ACAE sheet.On the other hand,it is related to the texture weakening caused by extrusion,especially ACAE sheet because of the introduction of ND(normal)and TD direction strain gradient,the basal texture is significantly weakened.

关 键 词：反对称弧形非对称挤压 传统挤压 镁合金薄板 三向单向拉伸 电子背散射衍射 

分 类 号：TH142.3[一般工业技术—材料科学与工程] TG379[机械工程—机械制造及自动化]