Effect of filler wire and post weld heat treatment on the mechanical properties of laser beam-welded AA2198

Highlights: • The chemical composition of the ALW and NLW joints play a key role on the tensile mechanical properties. • AA4047 filler wire increases the Si and Cu content in the grain interior and grain boundaries of the FZ. • The strong deformation texture of the NLW HAZ was completely resolved and replaced by a weak texture in the center of the FZ. • Deformation texture of BM does not present any significant change in the macrotexture, after heat-treatment. • After PWHT, yield stress attains higher values in 48 h/170 ^oC for both ALWed and NLWed joints. The mechanical behavior of autogenously and non-autogenously laser beam-welded joints of Al-Cu-Li alloy AA2198 and the effect of post weld heat treatment are examined in this contribution. The deformation texture of the base material does not present any significant change in the macrotexture with applying different artificial ageing times. Autogenously and non-autogenously laser beam-welded joints present a decrease in yield stress and ultimate strength in the as-welded condition, approximately 45% and 36–38%, respectively, when compared with AA2198-Τ3 base material. The addition of the AA4047 filler wire increases the Si and Cu content in the grain interior and in the grain boundaries of the fusion zone of the welded joint. Micro-hardness measurements for autogenously laser-welded joints showed a decrease in hardness by 27% for the fusion zone and 42% for the heat-affected zone, when compared with the non-autogenously laser beam-welded joints. Α quality index was exploited to evaluate the tensile mechanical performance of the welded joints. It is observed that the non-autogenously welded joints always show a higher 'quality' than the respective autogenously welded joints and the highest quality index in terms of mechanical performance is achieved for the as-welded and the peak-aged conditions, respectively. Regardless of the post weld heat treatment condition, both autogenously and non-autogenously laser-welded specimens fractured in between the equiaxed and fusion zone during tensile loading.