Wire-Laser Metal Deposition (W-LMD) is a transformative additive manufacturing technology that utilizes a laser heat source to melt metallic wire feedstock for the high-efficiency fabrication of large-scale, near-net-shape components. The technology is distinguished from other manufacturing processes due to its high material utilization efficiency and superior safety compared to metal powder-based systems. W-LMD systems are composed of a focused laser, a wire feeder mechanism, a multi-degree of freedom motion system, cooling system, and a shielding gas supply to prevent oxidation. Deviation in process parameters of the system components can lead to external defects such as stubbing (insufficient melting) and dripping (melting above the melt pool), or other forms of internal defects such as porosities. A key feature of W-LMD systems is their capability of fabricating bimetallic structures. This paper reviews key studies on W-LMD systems and their advancements in bimetallic fabrication. The review highlights the current gaps and required research work in the field for bimetallic W-LMD manufacturing and its significance.
Additive manufacturing (AM), particularly laser-directed energy deposition (DED), provides an effective approach for fabricating multi-material metallic structures with tailored regional properties. However, joining dissimilar alloys remains challenging because of differences in thermal and mechanical properties, which can lead to interfacial defects, cracking, and reduced mechanical performance. This study investigates the interfacial characteristics and mechanical performance of stainless steel 420 (SS420) and Inconel 718 (IN718) multi-material structures fabricated using laser DED. Two bonding approaches were investigated: direct deposition of IN718 onto SS420 and the incorporation of a fixed-composition transition zone consisting of 25
Laser pulse-processed surface micro-dimples have critical applications in biomedical, optical, and automotive component manufacturing. The precise topographical characterization of these micro-dimples is strongly influenced by the laser fluence generated under varying processing parameters. This study presents a three-dimensional transient thermo-physical model to simulate the formation of micro-dimples under pulsed laser processing conditions. The novelty of the proposed modeling lies in its dynamic integration of heat transfer and phase transformation phenomena during pulsed laser interaction. Unlike conventional models, it accounts for rapid thermal gradients and their effect on micro-dimple morphology with high fidelity. Key input parameters, including laser power ( P ), pulse frequency ( f ), and pulse width ( P_w ) are varied across multiple simulation runs. The resulting geometric characteristics micro-dimple diameter, depth, and spacing are recorded as output responses. Experimental validation is carried out using a pulsed Nd:YAG laser on a Ti-6Al-4V substrate. Confirmatory formation of a hardened oxide layer on the surface, which is beneficial from a tribological perspective. The numerical model demonstrated strong predictive accuracy, with a mean deviation of just 10.39
This investigation studies the variations in laser power and dry sliding conditions influence on the tribological performance of NiCrBSi alloy materials laser-cladded on steel alloy substrate. Alloy coatings were deposited using three different laser powers of 1500, 2000, and 2500 W. The coating deposited at 2000 W laser power showed well-refined microstructure, with X-ray diffraction (XRD) results correlating closely with the usual NiCrBSi phase composition. The coating also achieved a highest microhardness value of 675 HV0.5. Tribological behavior was assessed using a pin-on-disc tribometer at room-temperature, with varying sliding velocities (1.5, 2.5, and 3.5 m/s) and applied loads (10, 20, and 30 N) as test variables. At 1.5 m/s sliding velocity, the wear rates recorded for the 1500, 2000, and 2500 W laser powers processed samples were 0.145, 0.11, and 0.125 mm3/m respectively. The coating deposited at 1500 W laser power predominantly exhibited adhesive and delamination wear mechanisms, attributed to lower densification and a coarser microstructure. The coating deposited at 2000 and 2500 W laser powers showed more refined microstructures that favoured a transition toward abrasive wear, which is generally more stable under sliding conditions. Higher laser powers promoted the formation of hard intermetallic phases, such as M23C6, M7C3, and CrB, contributing to abrasive wear. In contrast, lower powers were more prone to adhesive wear due to low pronounced phase development.
This study uses an in-situ synthesized CoCrNi multi-principal element alloy (MPEA) interlayer to suppress brittle intermetallic compounds (IMCs) in laser-welded 5A06/316L dissimilar joints. The microstructure and mechanical properties of the joints were systematically examined under various welding parameters. Experimental results demonstrate that a sound joint with optimal tensile strength of 121 MPa was achieved at a laser power of 2500 W and a welding speed of 45 mm/s. SEM analysis confirmed that the in-situ formed FeCoCrNiAl medium-entropy alloy transition layer promoted more uniform elemental intermixing of Fe and Al. It effectively inhibited the excessive growth of detrimental Fe-Al IMCs. Numerical simulations further elucidated the correlation between weld pool dynamics, interlayer behavior, and IMC formation. This work provides a viable approach for enhancing Al/steel dissimilar joints via an MPEA interlayer.
