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Evaluation of mechanical and interfacial properties of friction welded alumina-mild steel rods with the use of Al6061 sheet are presented in this work. SEM, EDX analysis, hardness and bending strength tests were conducted. The bonds were attained through interfacial interlocking and intermetalllic phase formation with average bending strengths in the range of 40 to 200 MPa and insignificant hardness change in the parent alumina and mild steel. A preliminary simulation was made to predict the deformation, stress, strain and temperature distribution during the joining operation using a fully coupled thermo-mechanical FE model. The aluminum alloy metal being rubbed was simulated using a phenomenological Johnson-Cook viscoplasticity material model, which suited for materials subjected to large strains, high strain rates and high temperatures. The highest stress, strain and deformation are found to be within the heat affected zone of the weld close to the periphery rubbing surface region and correspond to the highest temperature profiles observed.

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Numerical model of friction welding between ceramic and metal rods are established to predict temperature rises during the initial phase of the process. In this study alumina(ceramic) and mild steel(metal) rods are used and joined with aluminium sacrificial interlayer. The workpieces are welded together by holding alumina still, while rotating the steel attached with aluminium piece under influence of an axial load which creates frictional heat in the interfaces. The transient thermal response in welding is hard to model analytically. Generally, heat is dissipated over time scales of less than two seconds. For the thermal model, an explicit one dimensional (1-D) finite difference (FD) method is utilized to approximate the heating and cooling temperature distribution of the joined dissimilar rods. The preliminary predictions are compared to actual thermocouple data from welds conducted under identical conditions and are shown to be in fair agreement. Even though the FD method proposed in this study cannot replace a more accurate numerical analysis, it does provide guidance in weld parameter development and allows better understanding of the friction welding process.