Improvement of Load Bearing Capacity of Al-1100 Joining area by using In-situ Synthesizing of Al/Cr during FSSW

In-situ synthesizing of Al/Cr was carried out to improve the strength of spot joining of Al plates. For this purpose, 0.03gr Cr powder with 10 μm particle size was inserted in the spot joining zone and the assembly was subjected to the Friction Stir Spot Welding Process (FSSW). Microstructure, formation of intermetallic compounds and mechanical properties of samples were investigated by optical microscopy (OM), scanning electron microscopy with spot and line EDS, tensile and microhardness measurements. Spot and line scan chemical analysis (Spot-EDS and Line-EDS) of joining area indicated that minimal tool rotation speed for formation of Al-Cr intermetallic compounds (Al13Cr2) is around 2500 rpm. Formation of Al-Cr rich intermetallic compounds in the joining area increased the hardness of joining zone more than two times of hardness of join without this components (140±5 HV and 60±5 HV). Furthermore, in-situ synthesis joining increase ultimate tensile strength of the joint from 40±5 Mpa to 130±10 Mpa