Microstructure and Mechanical Properties of the Interface Between Co-extrusion of AA6060/AZ31 Bar with a Zn Layer.

The AA6O6O aluminum alloy and AZ31 magnesium alloy are prepared of coated bar by the forward isothermal extrusion, and the microstructure and mechanical properties of the Zn layer aluminum and magnesium composite bar are characterized by XRD,OM,SEM, EDS, micro hardness meter, etc. The results showed that at the extrusion temperature of 360 °C,the Al/Zn/Mg interface was well bound and no obvious defects were found. The addition of Zn effectively reduced or avoided the formation of Al-Mg intermetallic compounds, and the diffusion of elements occurred in the interface to generate Mg-Zn eutectic phases MgZn, MgZn2 and Mg2Zn3 through metallurgical reactions. Compared to Al/Mg composite, Zn promoted the AZ31 grain refinement, and the grains of less than 5 µm increased by 3. 91 %. The Mg-Zn eutectic phase at the interface significantly increased the microhardness value up to 163. 1 HV, which was about 30 HV higher than that of the Al/Mg interface,and the sheer intensity of the Al/Zn/Mg interface was enhanced by 30. 74%. [ABSTRACT FROM AUTHOR]