Improvement in microstructure and mechanical properties of wire arc additively manufactured 7075 aluminum alloy via adjusting TiC particle addition

7075 aluminum alloys with varying TiC particle additions were fabricated by simultaneously depositing a standard 7075 wire and a TiC treated wire at different wire feed speed ratios. The effects of TiC content on the microstructure and mechanical properties of 7075 alloy were investigated. Results indicated that the addition of TiC particles can effectively refine the grain structure through heterogeneous nucleation, and the grain refinement effect was enhanced with increasing TiC particle content in the range of 0-0.70 wt%. Moreover, TiC particles can restrain the continuous distribution of second phase at grain boundaries. TiC particles tended to cluster at grain boundaries as its content exceeded 0.48 wt%, which adversely affected their beneficial effect on the improvement of mechanical properties. At an optimal TiC content of 0.48 wt%, the tensile strength and elongation in the horizontal direction exhibited remarkable enhancements of 27.2% and 319%, respectively, compared to those without the addition TIC particle.