PSI - Issue 71

Ravi Prakash et al. / Procedia Structural Integrity 71 (2025) 325–332

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Fig. 7. Three-dimensional residual stress contour for longitudinal stress evolution in build part: (a) case-I, (b) case-IV, (c) case-II, (d) case-III.

5. Conclusions The present study employs three-dimensional FE-based thermo-mechanical modelling to study the impact of laser power and scan speed on thermal behaviour and residual stresses during the LPBF process, focusing on the multi track, multi-layer deposition of a cuboid Ti-6Al-4V alloy part on a substrate made of the same material. Prominent conclusions that can be extracted from this study are the following: ● At 500 W power, increasing the scan velocity from 5 to 20 mm/s decreases the temperature by 51.32%. At 2000 W power, the same velocity increase reduces the temperature by 50.42%. Reducing power from 2000 W to 500 W at a scan velocity of 5 mm/s drops the temperature by 54.94%, while at 20 mm/s, it results in a 55.76% decrease. These results suggest that the impact of laser power on the average surface temperature is stronger than scan velocity. ● Mechanical simulation results show that increasing the scan velocity from 5 to 20 mm/s raises residual stress by 66.9 MPa at 500 W power and by 190.9 MPa at 2000 W. As the laser scan velocity increases, the melt pool size decreases, increasing the temperature gradient and cooling rate, which leads to higher residual stress. ● At 5 mm/s, increasing power from 500 W to 2000 W decreases residual stress by 67.7 MPa, while at 20 mm/s, it reduces stress by 56.3 MPa. Higher laser power expands the HAZ, reducing the temperature gradient and lowering residual stress. Acknowledgements The authors would like to thank Dr B R Ambedkar National Institute of Technology, Jalandhar, for providing the licensed version of ABAQUS commercial software for the execution of process modelling. References Balbaa, M. A., Elbestawi, M. A., and McIsaac, J. 2019. An experimental investigation of surface integrity in selective laser melting of Inconel 625. The International Journal of Advanced Manufacturing Technology, 104(9 – 12), 3511 – 3529. Behseresht, S., and Park, Y. H. 2024. Additive Manufacturing of Composite Polymers: Thermomechanical FEA and Experimental Study. Materials, 17(8), 1912.