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Item type:Publication, Access status: without files , Towards controlled processing of high-conductivity Cu alloy (CuCrZr) on Inconel (IN718) substrate through beam shaping and process control in PBF-LB/M(Elsevier, 2026-06-27); ; ; ; Multi-material components that combine high-temperature structural performance with high thermal conductivity are of growing interest for advanced engineering applications. Laser powder bed fusion of metals (PBF-LB/M) offers unique opportunities to fabricate such components with precise control over geometry and composition, but the early stages of multi-material deposition remain poorly understood. In particular, the influence of substrate properties and process variables on interface formation, intermixing control, and defect evolution has not been systematically studied, especially for challenging alloys like copper and nickel-based superalloys. In this work, single-track experiments are conducted to investigate the deposition of a CuCrZr alloy on an IN-718 substrate, targeting the reduction of interfacial intermixing while preserving bonding integrity. The effects of laser power, scan speed, and laser beam shaping on melt pool morphology, substrate remelting, and compositional control at the interface are evaluated. Ring-dominant beam profiles achieve higher Cu retention (up to 53.9 wt% for Mode 3 and 47.5 wt% for Mode 6, versus 39.7 wt% for Gaussian), suppress keyhole formation, and substantially reduce the heat-affected zone width from 45 to 115 µm for Gaussian sources down to below 20 µm for Mode 6, which additionally decouples HAZ extent from process parameters. Liquation cracking at the HAZ, associated with Laves phase along Nb-enriched grain boundaries, was observed exclusively under core-dominant, high energy density conditions. Single-track experiments were deliberately selected as they represent the earliest and most substrate-dominated deposition stage, where thermal gradients are steepest and substrate-driven cracking mechanisms are most directly isolated. These results establish a mechanistic framework for understanding early-stage multi-material deposition, informing process parameter design in more complex geometries and guiding future studies aimed at controlling interfacial intermixing, minimizing defects, and improving the reliability of multi-material additive manufacturing.Publicationtype: Journal Article39 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Role of laser beam shape and energy density in modulating surface quality, porosity, microstructure, and mechanical properties of PBF-LB/M Ti-6Al-4V(Elsevier, 2026-01-03); ; ; ; Beam shaping has recently gained attention as a means to mitigate the thermal gradients and melt-pool instabilities associated with conventional Gaussian beams in laser powder bed fusion (PBF-LB/M), which often lead to surface roughness, defects, and microstructural inconsistency. This study examines the effects of different beam shapes and volumetric energy densities (VEDs) on the surface quality, porosity, microstructure, and mechanical response of Ti-6Al-4V. Cubic specimens were fabricated on an Aconity MIDI+ system using Gaussian, core-ring, and ring beam profiles over a VED range of 78–341 J/mm³. The results show that beam shaping with optimized VED reduces porosity, refines microstructure, and enhances mechanical performance. The Gaussian beam performed well at low VEDs (≤130 J/mm³) but exhibited increased surface roughness and keyhole porosity at higher energy inputs (≥150 J/mm³), whereas the ring-based beams initially showed higher porosity at low VEDs but achieved ∼99.97 % relative density and smoother surfaces at higher VEDs. The ring beam promoted stable conduction-mode melting, continuous prior-β grain growth, refined α′ martensitic microstructures, and strong crystallographic texture. From a mechanical perspective, Vickers hardness values (370–400 HV) correlated with the observed microstructural features. In addition, the Gaussian beam exhibited higher indicative strength at low VEDs but deteriorated with increasing energy input, whereas the ring beam showed the opposite trend, reaching an ultimate tensile strength of 1192 MPa and ∼21 % ductility under optimal conditions. Beam behavior was further evaluated using areal energy density (AED) normalized to the melt-pool width, indicating that melt-pool stability and the resulting surface quality, porosity, and microstructural evolution are primarily influenced by the spatial distribution of laser energy rather than nominal energy metrics alone. These findings provide a physical basis for laser beam shaping as an effective approach to broaden the stable processing window and achieve defect-free, texture-controlled Ti-6Al-4V components.Publicationtype: Journal Article17 29