Indranil Manna

The present study deals with the formation of a TiC/TiN/TiCN dispersed surface on Ti6Al4V by preplacement of graphite powder and subsequent laser melting using a continuous wave diode laser. The effect of laser power and shrouding environment (argon and nitrogen) on microstructure, phase, wear resistance and corrosion resistance properties of the laser composite surfaced (LCS) Ti6Al4V were evaluated. Microstructural analysis revealed the in-situ formed TiC and Ti2C phases (under argon) and TiCN, TiN/Ti2N phases (under nitrogen) in α/α’ matrix with dendritic or granular morphology. The microhardness of the LCS Ti6Al4V was found to be directly proportional to the phase fraction of TiC/TiN/TiCN in the treated region, with values ranging from 800 to 2100 VHN, which was nearly 3–7 times higher than the substrate. A detailed investigation into the fretting wear behaviour of the LCS samples showed excellent resistance to wear and decrease in COF values under a certain set of laser parameters. The corrosion resistance in Hank’s solution revealed a significant decrease in kinetics of corrosion due to LCS especially in nitrogen environment. The mechanism of corrosion has been established.

This study investigates the potential of laser surface cladding (LSC) using two stainless steel alloys, austenitic (M1) and martensitic (M2), as a sustainable alternative to hard‐chrome plating (HCP). Comprehensive evaluations, including microstructure, phase aggregate, hardness, bending, and wear tests (sliding, abrasive, and erosive), conducted as per ASTM standards, followed by post‐wear damage analysis, reveal distinct performance advantages for each alloy clad. The M2 clad exhibits higher flexural strength and modulus, along with the lowest specific damage rate in both sliding and abrasive wear tests, attributes to its higher hardness and strength. The M1 clad, in contrast, shows the lowest coefficient of friction and superior erosive wear resistance, owing to its relatively ductile nature and the formation of stable oxide films. Overall, the results demonstrate that iron‐based laser‐clad coatings offer a technically effective and environmentally benign substitute for HCP, with application potential in hydraulic and mining components. While clad M1 is more erosive‐wear resistant, clad M2 is more suitable to withstand sliding and abrasive wear damage.

Laser additive manufacturing (LAM) efficiently fabricates metal parts with reduced cost, time, and increased design flexibility. Its ultrafast cooling preserves metastable microstructures, extends solid solubility, and imparts unique properties unattainable via traditional methods, making it ideal for creating and refurbishing components with enhanced lifespan and performance. However, LAM faces significant challenges when applied to copper (Cu) and aluminum (Al) based alloys due to their intrinsic high reflectivity to laser beams and thermal conductivity, which result in inadequate melting, poor intermixing, and defects such as porosity, cracks, and inhomogeneities. Optimizing the process parameters to mitigate these defects from the experimental insights alone is expensive, time-consuming, and constrained by inadequate knowledge of the coupling between fluid flow, thermal transport, phase change, and microstructure evolution. To address this deficit, we report an experimentally validated multi-physics modeling approach for laser powder bed fusion of Cu–Cr alloy, valued for its high electrical/thermal conductivity and wear resistance. The influence of various process parameters on the bonding between the overlapping tracks and surface microstructure and properties is assessed. Going beyond the previously reported studies that mainly focused on optimizing the laser parameters and quantifying widths and depths of the melt pool, our results could establish an explicit interlinkage between the thermal convection and microstructural evolution, thereby probing the root causes of poor bonding in the overlapping tracks. These findings reveal the mechanism of defect formation such as balling and porosity, unveiling the control of the melt flow dynamics necessary for achieving uniformly fabricated tracks and their bonding with the underlying substrate.