Microstructural and mechanical properties of welded SSM356-T6 and SSM7075-T6 aluminum semi-solid sheets by friction stir welding

Abstract

Friction Stir Welding (FSW) was the welding process applied in this research to join different grades of aluminum alloy sheets Semi-Solid Metal (SSM) 356-T6 and 7075-T6. The test pieces have dimensions of 50 mm × 100 mm × 4 mm. The effect of tool rotational speed on metallurgy, and mechanical properties of welding was investigated. Dissimilar butt joints were produced by using cylindrical pin with conditions of different tool rotation speed (710, 1,000 and 1,400 rpm) and welding speed (80, 112 and 160 mm/min). The welding microstructures showed three different areas including base metal, stir zone and thermo mechanical affected zone, which were directly affected by the rotation speed of tool. The butt joint rotation speeds 1,000 rpm provided the average maximum tensile strength 246.33 MPa. Rotational speed allowed material flow from the from to the rear of the tool. The heat generated from friction lead to microstructural change and promote good mix and adhesion of both materials.

Keywords

• Friction stir welding
• Dissimilar joined
• Aluminum alloy
• Semi solid