Microstructural Characteristics and Tensile Properties of Linear Friction-Welded AA7075 Aluminum Alloy Joints

Linear Friction Welding (LFW) has been a recently developed solid-state welding process, has capabilities to efficiently join heat treatable Aluminum alloys by limiting the time at the temperature of intermetallic compound formation during the weld cycle. The transverse tensile properties of LFW joints of AA7075 Aluminum Alloy was evaluated and correlated with the microstructural characteristics of the joint. The weld joints exhibited joint efficiency of 75% with the fracture at Thermo-Mechanically Affected Zone. The XRD pattern revealed the absence of major strengthening precipitate MgZn₂ in weld nugget and TMAZ of the LFW joint. The absence of strengthening precipitates and coarse grain structure led to the deterioration of the mechanical properties in the TMAZ. The fracture surfaces of the tensile specimens revealed the ductile mode of failure.