Effect of applied pressure on microstructure and mechanical properties of linear friction welded AA1050-H24 and AA5052-H34 joints

Linear friction welding (LFW) of AA1050 and AA5052 was performed at various applied pressures. The strengthening contributions of the joints were examined to investigate the relationship between the microstructure and mechanical properties. The dominant strengthening mechanisms at the weld centre of the AA1050 joint were both the grain-boundary strengthening and dislocation strengthening. While the weld centre in the AA5052 joint was dominated by the grain-boundary strengthening since the dynamic recrystallisation (DRX) during LFW was promoted due to the relatively low stacking fault energy (SFE). On the other hand, the strengthening mechanism in the regions away from the weld centre in the AA1050 and AA5052 joints was mainly dominated by the dislocation strengthening due to increased dislocation introduced during LFW.