Effects of material placement and speed of tool rotation on the tensile strength of dissimilar friction stir welded AA7075-T651 and AA1200-H19 aluminium alloys

This research looked at how material placement and tool's speed of rotation affects the tensile strength and hardness of weldment manufactured in a butt configuration. The 6 mm thick plates were joined while alternating the material positioning between advancing side and retreating sides. By changing the tool rotational speed and material placement, ten joints were fabricated and were subjected to mechanical tests, the hardness and tensile properties were evaluated. The result shows that maximum UTS values of 152.48 and 142.75 MPa were obtained for categories X and Y weldment with the placement of AA 1200 on advancing and retreating sides separately at 1500 rpm speed of rotation with superior surface outlook while lowest values of UTS of 115.5 and 111.51 MPa were obtained for categories X and Y when AA1200 was placed on the advancing and retreating sides separately, maximum and minimum hardness for category X was 97 and 70.6 HV while for category Y it was 85.5 and 66.4 HV. It was concluded that category X weldment gave better mechanical properties. Hence softer materials should be positioned on advancing side.