PSI - Issue 56

Sapam Ningthemba Singh et al. / Procedia Structural Integrity 56 (2024) 11–18 Sapam Ningthemba Singh et al./ Structural Integrity Procedia 00 (2023) 000–000

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Fig. 4: SEM images of the fractured surfaces in (a&b) LDED only and (c&d) LDED+LSPed fractured surface.

4. Conclusions This research explored the high-layer thickness AM of Ti6Al4V alloy using the LDED process and enhancing the fatigue performance of these fabricated parts by using the LSP process. The surface micro-cracks were eliminated after polishing. These cracks are common to both AM and welding processes due to extreme temperature gradients. The fatigue life of the samples increased at first as the power increased, but a decreasing trend was observed due to longer cooling time, leading to coarser grains. Significant improvement in the fatigue life in samples 1 (56.51%) and 4 (39.26%) was observed for the LDED+LSPed. However, for samples 2 and 3, a slight decrease of 0.99% and 11.40%, respectively, in fatigue life, were observed for LDED+LSPed samples as compared to the LDED-only samples. Gaps seen in the LSPed area in samples 2 and 3 were the primary reason for the decrease in fatigue life. Internal defects and voids are also another reason for the decreased fatigue life. Acknowledgments The authors thank the Ministry of Education, Government of India, and Indovation Lab, NIT Silchar for providing financial and material support. The authors also thank CFM, VIT Vellore for allowing access to the LSP system. The authors acknowledge the advanced manufacturing lab, weld and corrosion lab, NIT Silchar for optical microscope and polishing facility, CIF IIT Guwahati for SEM facility, and Material characterization lab IIT Hyderabad fatigue testing facility.