Comparative analysis of WLAM techniques in pulsed and un-pulsed modes: performance, microstructure and mechanical properties

Purpose This study aims to determine the influence of the effect of pulsation in wire laser additive manufacturing (WLAM) on the performance of ER308 stainless steel for applicability in critical industries. Design/methodology/approach ER308 stainless steel walls were fabricated using WLAM in pulsed and un-pulsed. Microstructural analysis was conducted via metallography, while mechanical properties were assessed through hardness, Charpy impact and tensile testing. Fractography was performed to evaluate failure mechanisms. Findings In the un-pulsed mode, samples exhibited a dual-phase microstructure, consisting of austenite with some ferrite. The pulsed mode resulted in a higher fraction of ferrite and finer grains due to rapid solidification and thermal cycling. Pulsed specimens displayed a more uniform hardness distribution, with values ranging from 165 Hv at the bottom to 230 Hv at the top, reflecting fine grain structures. Charpy impact tests showed an approximately 29.2% increase in energy absorption for pulsed specimens. Tensile testing revealed pulsed specimens had a higher ultimate tensile strength (853.47 MPa vs 831.25 MPa) and fracture strain (42% vs 38%). Fractography confirmed ductile failure in pulsed specimens and brittle fracture in un-pulsed specimens. Research limitations/implications This study is limited to ER308 stainless steel and specific WLAM parameters. Future work should explore other materials and process variations. Practical implications Pulsed WLAM improves mechanical performance and uniformity, making it suitable for aerospace, energy and automotive applications. Originality/value A direct comparison of pulsed and un-pulsed WLAM of stainless steel.