Rotary friction welding on dissimilar metals of aluminum and brass by using pre-heating method

Continuous drive rotary friction welding was conducted on dissimilar metals of aluminum and brass. A pre-heating method was applied at temperature of 330 °C and 600 °C, which aims to soften brass (i.e., the hard side), so that, at the friction interface, both metals could deform accordingly. The deformation rate was calculated by using a constitutive equation. The joint strengths were measured by tensile test. The joint microstructure and chemical compositions were studied by SEM and EDS. According to the results, without pre-heating, the joint preserves a low strength as 35% of the base metal (aluminum). At pre-heating of 330 °C, the joint strength raised to 70% of the base metal (aluminum) corresponding to apparent plastic flow on brass side as calculated and experimented. A narrow intermetallic compound layer was formed indicating metallic bonding formed on the interface. However, at pre-heating of 600 °C, the strength of joint was only 27% of the base metal (aluminum). The microstructure examination shows excessive intermetallic compound that has formed on the interface indicating overheated temperature. The result is prospective as a sound joint of aluminum and brass could be obtained by further regulating both metals into deformation at the interface, in which pre-heating on the hard side was proved applicable.