Improving microstructure and properties of aluminum/steel joint effectively with friction extrusion welding process

We studied the joining of Chinese antirust aluminum alloy LF5 to Chinese mild steel A3 by the newly developed friction extrusion welding process, which has been successfully applied in welding aluminum/steel electrolytic electrodes. Sections 1 and 2 of this paper explained and evaluated the improvement mentioned in the title, which we believe is effective; they analyzed the influences of process parameters on the joint microstructure, mechanical properties and electric conductivity to obtain the optimal process parameters. The experimental results, presented in Figs. 2 and 3 and Table 4, and their discussion show that: (1) the strength of the joint obtained by the friction extrusion welding process is indeed improved; (2) both the joint mechanical properties and electric conductivity can meet the requirements of industrial production; (3) the optimal parameters obtained in this study are: rotating speed 1000 rpm, friction pressure 2.5 MPa, friction time 7s, forging pressure 3.5 MPa and forging time 4s.