铝合金包覆镁合金改善耐蚀性的挤压制备方法

Mg alloy AZ31 rod with a thin sleeve of Al alloy 6082 was fabricated using a co-extrusion processing. The thin Al alloy sleeve serves as a barrier to protect the Mg alloy core from corrosion. The influence of bimetal co-extrusion on microstructure and texture of the extruded rod is systematically studied using scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD) analysis. A comparative study about electrochemical behavior of the Mg alloy core and the Al alloy sleeve is also addressed. Our results show that the Al alloy sleeve is uniform and exhibits excellent bonding with the Mg alloy matrix. The co-extrusion of bimetal billet benefits grain refinement of Mg alloy and hardly change the typical extrusion texture with c-axes of grains largely perpendicular to the extrusion direction. Electrochemical analysis demonstrates that the Al alloy sleeve has much better corrosion resistance than the Mg alloy core.