Explore the vast range of titles available.

Multi-beam laser cladding uniformly heats a powder to form a cladding layer. However, the temperature of the powder reaching the substrate is inhomogeneous due to the powder size distribution. Herein the effect of the powder size distribution on layer formation during multi-beam laser cladding is investigated by evaluating pure copper layers formed on stainless steel substrates using copper powder with different particle sizes. A layer forms at a power density of 3.6 × 10 4  W/cm 2 or higher for powders with an average particle size of 30 μm but the iron component in the pure copper layer increases as the power density increases. Additionally, a layer forms at 2.0 × 10 4  W/cm 2 or higher with an average particle size of 20 µm. Furthermore, the volume of layer formation per energy (deposition efficiency) increases with an average particle size of 20 μm. A method, which efficiently forms a cladding layer, should realize economical methods to form copper cladding layers with excellent properties.

This research established half of the finite element model to investigate the thermal and stress field evolution of single track cladding deposited by the wide-beam laser. The proposed FE model is validated by the molten pool temperature measured by a pyrometer. And the characteristic of the cladding shows good agreement with the temperature profile. Based on the temperature data, the molten pool length, width, and depth are calculated. Meanwhile, the effect of process parameters including laser power and scanning speed on the molten pool dimensions, temperature gradient G , cooling rate ε , solidification rate R , and G / R are discussed. Three experiments under different process parameters are conducted to verify the simulation results. Furthermore, the thermal stress distribution of the cladding in different direction and different path are discussed. The results indicate that laser power and scanning speed have a significant influence on the thermal and stress field evolution.

Preparing copper matrix composite coating on Cu substrate by laser cladding method is difficult since high thermal conductivity and low absorption rate of Cu to infrared wavelength along with the complex influence of multi-processing parameters. In this work, laser beam power, defocus distance, and scanning speed are considered as the key factors influencing the coating quality, and output response includes the dilution ratio, clad height as well as clad width. By establishing a regression model between processing parameters and output response, an optimized craft to prepare high-quality copper matrix composite coating on the copper substrate was finally provided. Results indicate that the clad height and width increase with enhancing laser beam power but decrease with growing scanning speed. In addition, the dilution ratio increases with enhancing scanning speed and decreasing defocus distance. The mathematical model based on response surface methodology is credible to predict the key laser cladding parameters on dilution ratio, clad height and clad width within the error of 20%. By carrying out optimization via the desirability function, the optimum parameters achieved are laser beam power 1780 W, defocus distance 8.3 mm and scanning speed 789 mm/min.

This research developed an interaction model for the laser and powder during wide-beam laser cladding by lateral powder feeding. According to the wide-beam laser energy distribution and powder concentration distribution, and the geometrical positional relationship between laser beam and powder flow, a wide-beam laser-powder interaction model was built. This interaction model includes laser energy attenuation model and powder particle temperature distribution model. An attenuation coefficient was proposed to describe the laser energy distribution attenuated by the powder flow in laser-powder interaction zone. Furthermore, the effect of main parameters on the interaction model was discussed. The results show that the distribution of the attenuation coefficient and the powder temperature are asymmetrical. Laser power has no effect on the attenuation coefficient, and powder feed rate has no influence on the powder temperature distribution in wide-beam laser cladding.

The rectangular spot laser cladding system, due to its large spot size and high efficiency, has been widely applied in laser cladding equipment, significantly improving cladding’s efficiency. However, while enhancing cladding efficiency, the rectangular spot laser cladding system may also affect the stability of the melt pool, thereby impacting the cladding’s quality. To accurately predict the melt pool morphology and size during wide beam laser cladding, this study developed a melt pool monitoring system. Through real-time monitoring of the melt pool morphology, image processing techniques were employed to extract features such as the melt pool width and area. The study used laser power, scanning speed, and the powder feed rate as input variables, and established a prediction model for the melt pool width and area based on Support Vector Regression (SVR). Additionally, an Ant Colony Optimization (ACO) algorithm was applied to optimize the SVR model, resulting in an ACO-SVR-based prediction model for the melt pool. The results show that the relative error in predicting the melt pool width using the ACO-SVR model is less than 2.2%, and the relative error in predicting the melt pool area is less than 9.13%, achieving accurate predictions of the melt pool width and area during rectangular spot laser cladding.

Composite coatings with in-situ-grown ceramic phases were created using Ti-35Al-15Si as the cladding material and laser cladding coaxial powder feeding method. The effect of laser power on the quality, organization, and properties of coatings was examined. The experimental results reveal that as laser power rises, penetrating cracks form in the cladding layer. Its fused cladding layer consists mainly of Ti-Al and Ti-Si phases. When the laser power increases, the dilution rate of the cladding layer also rises, resulting in an increase in the Ti-Al phase and a decrease in the Ti-Si phase. Its fused cladding layer’s hardness and wear resistance declined as laser power increased, peaking at 900 W and 829.36 HV.

Because of its flexibility, precision, and strong generalization capacity, machine learning offers a whole new research viewpoint to the fields of materials science and engineering when compared to traditional experimental and computer simulation methods. This paper adopts laser cladding cracking research as the application background. A prediction model for small datasets is established using well-developed prediction algorithms, and a crack prediction model with superior generalizability, accuracy, and efficiency for cladding is proposed. The findings indicate that the tendency to crack increases with scanning speed, but it decreases with laser power; the random forest-based crack density prediction model has an accuracy of 90.1% and a coefficient of determination of R 2 = 0.874, which can better realize the prediction of the density and enhance some engineering practice guidelines.

Laser cladding technology is an advanced material surface modification technology, which has the advantages of a small dilution rate, a dense microstructure of the cladding layer, a good combination between coating and substrate, and no pollution of the working environment. The research progress of laser cladding is reviewed from three aspects: background types, basic principles, and research status. In the background category, the preset coating method and synchronous powder feeding method used in laser cladding technology are described. The research status of laser cladding technology is summarized from the aspects of cladding material, performance, and industrial application. Finally, some suggestions are put forward to obtain the cladding layer with no crack and good mechanical properties, and more technologies and laser cladding technology are expected to be combined in the future.

Surface texture is one of the hot spots in the field of surface tribology. It promotes friction by storing lubricating oil and abrasive particles, and in some cases it can also improve hydrodynamic effects. Since it has been widely used in mechanical parts, tribological characteristics and surface quality cannot be ignored. Nowadays, there are many ways to fabricate surface texture. Several classification methods based on different processing principles are introduced in this paper. It includes direct laser ablation, mechanical processing, EDM and ECM in material reduction processing, laser cladding, deposition method, and electroforming in additive processing and laser shock processing in deformation processing. The surface texture with good quality can be obtained by selecting proper machining method and proper machining parameters. The machining principle of each method, the research status of surface morphology of surface texture, and the advantages and disadvantages of each method are summarized. Finally, potential hybrid processing methods including their advantages and disadvantages as well as examples are presented.

Titanium (Ti) and its alloys have been widely employed in aeronautical, petrochemical, and medical fields owing to their fascinating advantages in terms of their mechanical properties, corrosion resistance, biocompatibility, and so on. However, Ti and its alloys face many challenges, if they work in severe or more complex environments. The surface is always the origin of failure for Ti and its alloys in workpieces, which influences performance degradation and service life. To improve the properties and function, surface modification becomes the common process for Ti and its alloys. The present article reviews the technology and development of laser cladding on Ti and its alloys, according to the cladding technology, cladding materials, and coating function. Generally, the laser cladding parameters and auxiliary technology could influence the temperature distribution and elements diffusion in the molten pool, which basically determines the microstructure and properties. The matrix and reinforced phases play an important role in laser cladding coating, which can increase the hardness, strength, wear resistance, oxidation resistance, corrosion resistance, biocompatibility, and so on. However, the excessive addition of reinforced phases or particles can deteriorate the ductility, and thus the balance between functional properties and basic properties should be considered during the design of the chemical composition of laser cladding coatings. In addition, the interface including the phase interface, layer interface, and substrate interface plays an important role in microstructure stability, thermal stability, chemical stability, and mechanical reliability. Therefore, the substrate state, the chemical composition of the laser cladding coating and substrate, the processing parameters, and the interface comprise the critical factors which influence the microstructure and properties of the laser cladding coating prepared. How to systematically optimize the influencing factors and obtain well-balanced performance are long-term research issues.