Laser Cladding Research Articles

Effect of Gradient Transition Layer on the Cracking Behavior of Ni60B (NiCrBSi) Coatings by Laser Cladding

Laser cladding technology is an effective method for producing wear-resistant coatings on damaged substrates, improving both wear and corrosion resistance, which extends the service life of components. However, the fabrication of hard and brittle materials is highly susceptible to the problem of cracking. Using gradient transition layers is an effective strategy to mitigate the challenge of achieving crack-free laser-melted wear-resistant coatings. This study presents the cracking issue of laser cladding Ni60B (NiCrBSi) coatings on 38CrMoAl (18CrNiMo7-6) steel by designing a gradient transition layer infused with varying amounts of Ni powder. We examine how different levels of Ni doping in the transition layer influence the fabrication of the Ni60B coating. The results indicate that the cracking mechanism of Ni60B is primarily due to the brittleness and hardness of the fusion cladding layer, which can result in cold cracks under residual tensile stress. Increasing the nickel content in the transition layer reduces the difference in thermal expansion coefficients between the cladding layer and the substrate. Additionally, the nickel in the transition layer permeates the cladding layer due to the laser remelting effect. The physical phase within the cladding layer transitions from the initial CrB, M7C3, and γ-Ni solid solution to γ-Ni solid solution and Ni-B-Si eutectic, with a small amount of boride and carbide hard phases. As the nickel doping in the transition layer increases, the proportion of the toughness phase dominated by Ni elements significantly rises, leading to a decrease in the hardness of the fused cladding layer. However, the average hardness of the fusion cladding layer in crack-free samples was measured at 397.5 ± 5.7 HV0.2, which is 91% higher than that of the substrate.

Numerical simulation and structure properties of laser clad 316 L stainless steel coating

Numerical simulation and structure properties of laser clad 316 L stainless steel coating

Influencing mechanism of the active elements on the surface tension of the laser cladding molten pool and the determination of the critical concentration

The addition of active elements during cladding will affect the molten pool flow, and different concentrations have different flow states. In this paper, a numerical model of heat-flow coupling in the ASTM 1045 laser cladding Fe60 process was established and the effects of different concentrations of S, O, and Se elements on the molten pool flow state were calculated and revealed. The results show that there is a critical concentration (CC) when the active element affects the molten pool flow. When the concentration is lower than CC, the flow direction of the melt in the molten pool is from the center to the edge. With the increase in concentration, the flow velocity of the molten pool gradually decreases. When the concentration of active elements reaches CC, the flow direction of the melt changes, but the concentration will make the molten pool flow disorderly appear. The concentration at which the melt flow direction begins to change is called the initial critical concentration (ICC), and the concentration at the end of the change in the melt flow direction (completely reversed) is called the perfect critical concentration (PCC). In the experiment, ICC and PCC intervals are not suitable for concentration selection. When the concentration of active elements exceeds PCC, the flow direction of molten pool does not change. The flow velocity of the molten pool gradually increases with the increase in the active element concentration. The morphology and microstructure of the cladding layer were analyzed with the same technological parameters. The effectiveness of numerical simulation is verified.

Effect of Ni–Bi Alloying on the Microstructure and Self‐Lubricating Properties of CoCrNi‐Based Coatings Across a Wide Temperature Range

This study investigates the use of bismuth (Bi) as a lubricating additive in laser cladding Co‐based composite coatings, addressing the issue of Bi segregation and agglomeration through Ni–Bi alloying. The microstructure, mechanical properties, and tribological properties of composite coatings with varying Ni–Bi contents are systematically evaluated at temperatures between 30 and 800 °C. Analysis reveals that Ni and Bi elemental powders are successfully alloyed to form BiNi and Bi3Ni intermetallic compounds following vacuum sintering. Incorporation of Ni–Bi alloying powder significantly enhances the friction coefficient and wear rates of the composite coating across the temperature range. Adhesive wear and abrasive wear are identified as primary wear mechanisms. Notably, the formation of BiNi, multiple oxides, and Bi16CrO27 compounds on the surface of the 85:15 (at%) Bi:Ni composite coating at 600 °C created a self‐lubricating friction layer, synergistically reducing friction. Consequently, compared to Co‐based alloy coatings without Ni–Bi alloying, the composite coating exhibited a three‐fold reduction in friction coefficient and a two‐order‐of‐magnitude improvement in wear rate, demonstrating exceptional tribological properties.

Experimental Study of Stainless-Steel Nanoparticles Coating on Carbon Steel Using the Laser Cladding Approach

Experimental Study of Stainless-Steel Nanoparticles Coating on Carbon Steel Using the Laser Cladding Approach

Effect of Recovery Treatment on the Microstructure and Tribological Properties of Ultrasonic Impacted Al2FeCoNiCrW0.5 High-Entropy Alloy Coatings

To investigate the effect of recovery treatment on the microstructure and tribological properties of ultrasonic impact-treated Al2FeCoNiCrW0.5 high-entropy alloy coatings, laser cladding technology was used to fabricate coatings on a G10450 steel substrate, followed by ultrasonic impact treatment (UIT) and recovery treatment (HR, 300 °C). The results showed that the Al2FeCoNiCrW0.5 high-entropy alloy coating consisted of BCC and FCC phases. Ultrasonic impact treatment slightly broadened the XRD diffraction peaks, while the recovery treatment had minimal effect on them. Ultrasonic impact also refined the coating grains. Ultrasonic impact treatment increased the coating hardness from 738 HV0.5 to 856 HV0.5. Although the subsequent post-annealing slightly reduced the hardness to 806 HV0.5, it significantly improved wear resistance, with wear loss decreasing from 3.273 mm3 to 2.881 mm3, representing a 15% reduction in wear rate. The improvement in wear resistance was attributed to a change in the wear mechanism of the high-entropy alloy coating. Before and after post-annealing, the mechanism transitioned from abrasive wear, adhesive wear, and oxidative wear to primarily abrasive wear and oxidative wear. Additionally, the recovery treatment transformed the surface from hard and brittle to ductile and resilient.

Wear and Corrosion Resistance of 304SS Coating Using High Speed Laser Cladding

Wear and Corrosion Resistance of 304SS Coating Using High Speed Laser Cladding

Study on the performance of laser cladding Ni-based WC60 composite coatings

Nickel-based Tungsten Carbide (WC) materials have excellent wear resistance and high temperature stability. They are prone to cracking during laser cladding due to the rapid cooling and heating characteristics. The sensitivity of cracking differs when cladding different substrates, which is a bottleneck for the industry. Quantitatively revealing the laser cladding mechanism of nickel-based WC is significant for optimizing the process. In this paper, a coupling model of the thermal field, flow field, and stress field was established for the laser cladding of nickel-based WC60 on a 42CrMo substrate. The model considered the influence of the powder absorption, surface tension and buoyancy on the flow for liquid metal and focused on analyzing the transient evolution during laser cladding. Cladding samples were prepared and subjected to the X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), and microhardness characterization experiments. The morphology and mechanical properties of WC60 based on nickel were observed, and its solidification characteristics were analyzed. The calculations show that the maximum temperature during laser cladding reaches 2529 K, forming an upward Marangoni flow with a maximum velocity of 0.25 m/s. The thermal stress of the cladding layer reaches 616 MPa, and the residual stress reaches 647 MPa. The experiments show that WC particles are spherical and exist in the cladding layer as hard phases, deposited in the middle and lower parts of the cladding layer, which effectively enhances the hardness of cladding layer. WC particles impede columnar crystal growth, and some WC particle boundaries undergo melting, leading to the diffusion of tungsten elements into the cladding layer. This study provides a theoretical basis for optimizing the laser cladding process of nickel-based WC and improving the coating performance.

Study on the multifield coupling mechanism in laser cladding of 316L under different elevation angles of the laser head

Study on the multifield coupling mechanism in laser cladding of 316L under different elevation angles of the laser head

Study on the Effect of CeO2 on the Performance of WC + Ni60 Laser Cladding Coating

Study on the Effect of CeO2 on the Performance of WC + Ni60 Laser Cladding Coating

Effect of copper content on the microstructure and electrochemical corrosion behavior of laser cladding 316L stainless steel coating

Effect of copper content on the microstructure and electrochemical corrosion behavior of laser cladding 316L stainless steel coating

Microstructure and wear resistance of multi-layer graphene doped AlCoCrFeNi2.1 high-entropy alloy self-lubricating coating prepared by laser cladding

A novel AlCoCrFeNi2.1 high-entropy alloy self-lubricating coating was prepared by multilayer graphene (MLG) enhancement. The AlCoCrFeNi2.1-MLG (3 wt%) high-entropy alloy self-lubricating coating was prepared on AISI1045 steel using laser cladding by introducing lubricant named MLG. The microstructure, phase structure, wear resistance and corrosion performance of the AlCoCrFeNi2.1-MLG coating were studied. It is shown that the microstructure of the AlCoCrFeNi2.1-MLG coating has typical dendritic (DR) and interdendritic (ID) structures, with the dendrites consisting of high density M23C6 phase precipitation and FCC phase distributed in the interdendritic region. With the addition of MLG, the average hardness of the AlCoCrFeNi2.1 coating increases from 306.71 HV to 486.68 HV (an increase of 58.68 %). The average coefficient of friction decreases from 0.59 to 0.48 (a reduction of 22.92 %). The wear rate decreases from 1.678 × 10- 6 mm3·N− 1 m−1 to 0.825 × 10- 6 mm3·N− 1 m− 1 (a reduction of 50.83 %). This is due to the formation of a lubricant film in the AlCoCrFeNi2.1-MLG coating. The wear mechanism changes from plastic deformation and abrasive debris wear to slight delamination and spalling of the lubricant film. However, the corrosion performance of the AlCoCrFeNi2.1-MLG coating is slightly reduced by the occurrence of micro-electro-coupling corrosion on the corroded surface. The M23C6 phase is used as the anode and the FCC phase is used as the cathode. The subsequent generation of a passivation film prevents the appearance of severe electro-coupling corrosion. The wear resistance of the AlCoCrFeNi2.1-MLG coating is substantially improved while taking into account the corrosion performance. This study provides important values for laser cladding of self-lubricating composite coatings of high-entropy alloys.

Microstructure and tribological properties of WC-12Ni/Cu composite coating prepared by laser cladding on 45 steel surface

Abstract To reduce the amount of copper used and improve the service life of the copper layer in the plunger pair of a plunger pump, Ni15 was chosen as the transition layer to assist in the laser cladding preparation of copper-steel composite materials. WC-12Ni powder was mixed into Cu powder at concentrations of 5, 10, 15, 20, 25 wt%, and different compositions of cladding layers were prepared using laser cladding technology. The microstructure of the cladding layers was analyzed by optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). The microhardness of the composite coatings was tested using microhardness Vickers (MHV), and the tribological performance of the composite coatings was evaluated using the friction and wear testing machine (F&WM). The results showed that, in terms of microstructure, element diffusion occurred around the WC particles, and partial dissolution of WC particles at their sharp corners led to the formation of new compounds with other elements. Additionally, WC particles contributed to the refinement of the microstructure. In terms of performance, the microhardness of the composite coatings increased with the increase in WC-12Ni content, reaching a maximum of 412.5 HV0.1 when the content was 25 wt%. Regarding tribological properties, the composite coating with 20 wt% WC-12Ni exhibited excellent friction-reducing properties, with a stable coefficient of friction of 0.53. Both the 20 wt% and 25 wt% WC-12Ni composite coatings demonstrated good wear resistance, with wear rates of 4.4 × 10−4 mg/ N·m.

Enhanced wear resistance of CuSn19Ti10/Ni-coated diamond composite coatings prepared by laser cladding: Influence of nickel plating on diamond retention and microstructure

Enhanced wear resistance of CuSn19Ti10/Ni-coated diamond composite coatings prepared by laser cladding: Influence of nickel plating on diamond retention and microstructure

MAX phase coatings: synthesis, protective performance, and functional characteristics.

Mn+1AXn (MAX) phases are a novel class of materials with a closely packed hexagonal structure that bridge the gap between metals and ceramics, garnering tremendous research interest worldwide in recent years. Benefiting from their unique layered structure and mixed covalent-ionic-metallic bonding characteristics, MAX phase coatings possess excellent oxidation resistance, and exceptional electrical and thermal conductivities, making them highly promising for applications in advanced nuclear materials, battery plate protection materials, and aero-engine functional materials. This review aims to provide a comprehensive understanding of MAX phase coatings. It presents an overview of their compositions and microstructure, highlighting well-established structures like 211, 312, and 413. Furthermore, it delves into the various synthesis methods employed in fabricating MAX phase coatings, including physical vapor deposition, chemical vapor deposition, spraying methods, and laser cladding, among others. The potential applications of MAX phase coatings, high-temperature oxidation resistance, mechanical protection, salt spray corrosion resistance, etc., are also investigated. Finally, this review discusses the future potential of MAX phase coatings and proposes areas for further research and improvement. The primary goal is to offer theoretical guidance and innovative ideas for the synthesis and development of superior MAX phase coatings for commercial applications.

Microstructure, performance, strengthening and toughening mechanisms of WC-reinforced Inconel 625 gradient composite coating by laser cladding on nonmagnetic steel

Microstructure, performance, strengthening and toughening mechanisms of WC-reinforced Inconel 625 gradient composite coating by laser cladding on nonmagnetic steel

Effect of in situ NbC synthesis via laser cladding on microstructure and slurry erosion of carbide-reinforced iron-based coatings

Effect of in situ NbC synthesis via laser cladding on microstructure and slurry erosion of carbide-reinforced iron-based coatings

In-situ synthesized WC reinforcement phase on microstructural evolution, toughness and tribological properties of Mo2FeB2-based composite coatings fabricated by laser cladding

In-situ synthesized WC reinforcement phase on microstructural evolution, toughness and tribological properties of Mo2FeB2-based composite coatings fabricated by laser cladding

In-situ synthesized (Ti,Nb)C reinforced austenitic stainless steel by laser cladding: New insights into microstructure evolution and corrosion behavior

In-situ synthesized (Ti,Nb)C reinforced austenitic stainless steel by laser cladding: New insights into microstructure evolution and corrosion behavior

Multi-ceramic phases synergistically reinforced titanium matrix composite coating deposited by laser cladding: Effect of B4C content on the microstructure and wear properties

Multi-ceramic phases synergistically reinforced titanium matrix composite coating deposited by laser cladding: Effect of B4C content on the microstructure and wear properties