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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 Article37 - 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 Article16 24 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Influence of spatial tool inclination on delamination when milling CFRP(2018-02); When end milling long carbon-fibre-reinforced plastic (CFRP), delamination, mainly fibre protrusions can occur at the top layers of the machined edges. It was observed that the spatial inclination of the tool axis significantly influences delamination and has not yet been investigated in detail. The fibre cutting angle used so far for the description of the separation process only refers to the cutting velocity in the laminate plane. The spatial position of the cutting edge and the effective velocity with respect to the fibre axis of a unidirectional ply depend on the tool engagement angle and the inclination of the tool axis. Hence, a three-dimensional description of the geometrical and kinematic relationships has been established in this work for the first time. To determine the effect on delamination the model is compared to milling experiments with various tool axis inclinations towards and perpendicular to the feed direction, denoted by lead and tilt angle. The results show that fibre protrusions can be avoided if the cutting velocity is at least partially directed into the laminate plane and if the cutting edge is located partially above the fibre to be cut. The geometrical and kinematic model is applicable to any machining operation, to materials with unidirectional fibre reinforcement and to non-crimped fabrics with unidirectional top layers.Publicationtype: Journal Article119 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Influence of process-induced microstructure and imperfections on mechanical properties of AlSi12 processed by selective laser meltingSelective laser melting (SLM) offers high potential for manufacturing complex geometries and custom-made parts due to its unique layer-wise production process. A series of samples of AlSi12 have been manufactured by SLM process to study the effect of process parameters and post-build heat treatment on the microstructure and the corresponding mechanical properties. Optical microscope, scanning electron microscope, quasistatic tests, continuous load increase fatigue tests and constant amplitude fatigue tests have been employed for characterization. A remarkable eutectic microstructure, with dendritic width changing with SLM process parameters, has been observed. Relationship between SLM process parameters, resulting microstructure and the consequent changes in mechanical properties has been discussed. Base plate heating has been found critical in controlling the in-process microstructure. Mechanical properties of SLM parts outperform those of conventionally manufactured alloy, and can be varied as per requirement, by altering the build rate, keeping the process costs in control. Fatigue scatter can also be controlled by heating the base plate during the process.Publicationtype: Journal Article99 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Influence of weave structure on delamination when milling CFRPThe increasing use of carbon-fiber-reinforced plastic (CFRP) is, in addition to weight reduction, driven by decorative elements especially in the automotive industry. Different kinds of woven CFRP laminates are applied for visual effects, which, however, demand a high level of surface quality of the workpiece including the trimmed edges. This study is the first to investigate the correlations between weave induced fiber undulation and delamination when machining CFRP with a woven fabric. In order to analyze the influence of the undulation, several slots were milled into CFRP with a plain weave structure using polycrystalline diamond cutters. The relative position of the trimmed edge to the weave undulation was varied by inclining the milling path slightly relative to the fiber orientation. Surface damage and fiber protrusion from the trimmed edge were determined separately. To identify the fiber undulation angle and thickness of the top matrix layer, tomographic measurements of the laminate were used. Additionally, a theoretical model for maximum fiber protrusion was established. It became apparent that the combination of fiber undulation angle and thickness of the top matrix layer are responsible for different occurrences of delamination. The influence of tool geometry on delamination is less significant.Publicationtype: Journal Article99 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Comparison of coaxial and off-axis nozzle configurations in one step process laser cladding on aluminum substratePublicationtype: Journal Article4