Investigation on the mechanical properties of FSWed AA6063 – T351 aluminum alloy joints

Abstract

In order to assess the mechanical characteristics of a 5 mm thick AA6065 – T351 alloy, this research compared welding speed of 60, 80, and 100 mm/min with tool rotational speeds of 450, 650, 850, and 1050 rpm. Without any defects, all joints were prepared. The Ultimate Tensile Strength (UTS) values consistently exceeded 450 MPa, representing a minimum joint efficiency of 69.2%. The highest value, 451.6 MPa, was obtained for the junction made with a 450 rpm and a 100 mm/min (or 78.4% joint efficiency). The strongest joint's SZ had a grain size of 5.3 ± 2.1 µm and a microhardness (HV) of about 147 HV0.1. The low-hardness zone, also known as the TMAZ/HAZ interface, is where the tensile samples fail (107–114 HV0.1, depending on characteristics). The vast majority of fractures occur as a result of transgranular flexible fracture with micro-void coalescence.