Investigation of Mechanical Properties of the Al–Si–Mg Alloy Produced by Severe Plastic Deformation Technique Combined with the Friction Welding

In this study, equal channel angular pressing (ECAP) technique was used as the severe plastic deformation method. The ECAP process was applied to the samples of Al–Si–Mg alloy, which further were joined via the friction welding (FW) technique. ECAP was applied to the samples for up to two passes. Microstructural and mechanical characterization of the material, tensile and hardness tests, as well as the optical microscope (OM), scanning electron microscope (SEM), and fractured-surface examinations were performed after the homogenization process and after each ECAP pass. In the study, the FW joining of Al–Si–Mg alloy samples preliminarily subjected to ECAP process and the effects of microstructure on the mechanical properties of FW joining of ECAP materials were examined. The aim of the study is to examine the mechanical effect of the material, which is pre-processed with severe plastic deformation, on the friction welding. As a result, in mechanical properties, a 30–40% increase in hardness was observed in ECAP 1 and 2 passes compared to homogenized materials, while an increase in yield strength was observed in direct proportion to the increase in the number of ECAP passes. Reduction in grain sizes after the ECAP process positively affected the strength and hardness values.