Effect of deposition current on Fe3AlC0.5 precipitation in Fe3Al alloy fabricated via twin-wire directed energy deposition-arc process

Recent developments in materials engineering have introduced the twin-wire directed energy deposition-arc (TW-DED-arc) technique, which improves manufacturing flexibility and cost-effectiveness of Fe3Al-based iron aluminide alloys despite their inherent room-temperature brittleness. By incorporating in-situ generated Fe 3 AlC 0.5 precipitates into the Fe₃Al matrix, the Fe-30Al-0.3C-Si-Mn alloy exhibits significantly improved mechanical properties compared to the binary Fe-30Al alloy. In this study, multiple Fe-30Al-0.3C-Si-Mn samples were fabricated at different deposition currents to investigate the influence of current on Fe 3 AlC 0.5 precipitation and its strengthening mechanism in TW-DED-arc fabricated Fe₃Al-based alloys. A systematic analysis of deposition current effects on droplet transfer, molten pool temperature, microstructure, and mechanical properties was conducted. Tensile anisotropy and fracture behavior of the deposited alloy were also evaluated. Results show that increasing the deposition current raises the molten pool temperature and heat accumulation. Although higher currents modify the size and distribution of Fe 3 AlC 0.5 particles, the in-situ precipitates promote grain nucleation and inhibit grain growth, effectively maintaining the microstructure and mechanical properties of the alloy. These findings indicate that Fe 3 AlC 0.5 precipitates expand the feasible processing window of the TW-DED-arc technique and demonstrate the efficacy of this approach in optimizing the microstructure and mechanical performance of Fe-30Al-0.3C-Si-Mn alloys.