T6热处理对A356/6082铝合金复合板界面组织及力学性能的影响!

Effect of T6 Heat Treatment on the Interfacial Microstructure and Mechanical Properties of A356/6082 Aluminum Alloy Composite Plate

采用液-固轧制复合技术制备A356/6082层状复合板,并对其进行T6热处理。通过光学显微镜(OM)、扫描电镜(SEM)、剪切试验、显微硬度测试等表征手段对比分析了T6热处理前后复合板显微组织变化、界面元素扩散规律以及剪切强度和硬度等力学性能特征。结果表明:T6热处理后,层片状共晶硅形态发生球化,界面附近的共晶硅团聚现象消失且组织更为均匀;界面区Mg元素明显扩散,结合线消失;复合板剪切强度从91. 6 MPa提高到139. 2 MPa,界面区域和基体的显微硬度均得到明显改善,A356侧的平均硬度值达到1102. 5 MPa左右,6082侧的平均硬度值达到851. 6 MPa左右,且沿A356至6082垂直界面方向其显微硬度值逐渐下降。

A356/6082 composite plate was fabricated by liquid-solid rolling composite technique and subsequent T6 heat treatment.Microstructure changes of composite plate, interfacial element diffusion, mechanical properties of the shear strength and micro-hardness before and after T6 heat treatment were researched by optical microscopy (OM), scanning electron microscope (SEM), micro-hardness measurements and shear tests.The results showed that the morphology of eutectic silicon in the A356 aluminum alloy changes from long, coarse plate-like to fine spherical after T6 heat treatment.The eutectic silicon agglomeration near the interface disappeared and the microstructure is more homogeneous.Near the interface, the Mg elements obviously diffuse.In addition, the shear strength of composite plate increases from 91.6 to 139.2 MPa, and the micro-hardness near the interface and the substrate both increases significantly.The average hardness value of the A356 side reaches about 1102.5 MPa and the average hardness value of the 6082 side reaches about 851.6 MPa.Micro-hardness value of the A356 side to the 6082 side decreases gradually along the vertical interface.