正挤压-弯曲剪切变形AZ31/6061复合板组织及性能研究

Microstructure and properties of AZ31/6061 composite plate by direct extrusion and bending-shear deformation

利用正挤压-弯曲剪切变形技术成功制备出AZ31/6061层状复合板。通过DEFORM-3D有限元模拟,分析了正挤压-弯曲剪切变形过程中复合坯料的变形行为;采用金相显微镜、扫描电镜和万能拉伸试验机等检测手段,研究了正挤压-弯曲剪切变形AZ31/6061复合板的微观组织及力学性能。研究结果表明:正挤压-弯曲剪切变形的对称性模具结构设计可有效协调复合坯料变形过程中的等效应变、应力以及金属流速。在380℃下挤压变形制备AZ31/6061复合板,镁合金发生完全动态再结晶,平均晶粒尺寸可细化至1~2μm,铝合金晶粒沿着挤压方向被拉长。挤压后层状复合板力学性能优良,抗拉强度高达256 MPa,断裂伸长率为20.5%。

The AZ31/6061 composite plates were successfully fabricated by the direct extrusion and bending-shear deformation process.The deformation behavior of the composite billet during the direct extrusion and bending-shear deformation process was analyzed by DEFORM-3 D finite element simulation. The microstructure and mechanical properties of AZ31/6061 composite plate by direct extrusion and bending-shear deformation were investigated by optical microscope,scanning electron microscope and unversal tensile testing machine.The research results show that the symmetrical die structure design of direct extrusion and bending-shear deformation can effectively coordinate the equivalent strain,stress and metal flow rate during the deformation process of composite billet. When the AZ31/6061 composite plates were prepared at 380 ℃ by extrusion deformation,complete dynamic recrystallization occurs in magnesium alloy,the average grain size can be refined to 1-2 μm,the aluminum alloy grains are elongated along the extrusion direction. Excellent mechanical properties of the extruded composite plate are obtained,the tensile strength and the elongation can reach 256 MPa and 20. 5%,respectively.