Investigations on the influence of post weld heat treatment on fatigue crack growth behaviour of electron beam welded AA2219 alloy

This paper reports the influence of post weld heat treatment on fatigue crack growth behaviour of electron beam welded AA2219 aluminium alloy. An attempt has been made to enhance the fatigue crack growth resistance of the electron beam welded joints through post weld heat treatment methods such as solution treatment (ST), artificial aging (AA), solution treatment and artificial aging (STA). Electron beam welding machine with 100 kV capacity has been used to fabricate the square butt joints. Servo hydraulic controlled fatigue testing machine with a capacity of 100 kN has been used to evaluate the fatigue crack growth behaviour of the welded joints. Of the three post weld heat treated joints, the solution treated and aged (STA) joints are offering better resistance against the growing fatigue cracks. The superior mechanical properties, preferred microstructures in the weld metal region and favourable residual stress field of the weld region are found to be the reasons for superior fatigue performance of the STA joints compared to other joints.