Investigations on work hardening behaviour and relative slip distance in GTA welded AA 6063 plates using AA 5356-TiB2 filler rod

The present work deals with the enhancement of the tensile strength of AA 6063 plates welded by the GTAW technique using AA 5356 filler metal sprayed with TiB2 nanoparticles (0, 4, 8 and 12 wt%). Advanced characterization techniques were used to observe microstructural variations and correlate them with the properties of the tensile curves. The X-ray profiles revealed the absence of a thermochemical reaction, variations in the position and intensity of the α-Al peak in the weldment. The IPF micrographs revealed the refined grains in the α-Al phase owing to the incorporation of TiB2 nanoparticles which prevented the nucleation of grain growth according to the Zener pinning effect (0 and 12 wt% TiB2 weld: 103 ± 8 and 26 ± 8 μm, respectively). The pole figures show that the weakened texture in the planes can be attributed to the severe deformation of the grains (0 and 12 wt% TiB2 weld: 6.086 and 1.842, respectively). The engendered strain fields and accumulated dislocations enhanced the load-carrying ability of α-Al weldments. These factors improved the mechanical strength of the weld. The 12 wt%TiB2/α-Al weld demonstrated the higher work hardening rate. Increases in the strain hardening exponent provided more plastic properties and a decreased relative slip distance extended the occurrence of deformation during tension.