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Dilution rate is an important factor affecting the properties of laser cladding. However, the exact estimate of dilution rate in direct laser fabrication is still not fully developed. In this study, high-strength and wear-resistant YCF102 alloy powder is used to laser clad on the steel substrate. The area of the cladding layer is replaced by a part of the circle, and the relationship among the deposition angle, the clad width, and the area of the cladding layer is established. The geometry of the fusion zone is replaced by polynomial function of the fourth degree, and the relationship among the thermal tension angle, the clad width, the melting pool depth, and the area of the fusion zone is established. The value of the dilution rate is obtained by the area of the cladding layer and the fusion zone. The correlation coefficient of the area of cladding layer, the area of the fusion zone, and the dilution rate is also obtained. The estimate results coincident with the measurement results very well. The proposed theoretical model offers a basis for estimate of dilution rate in laser cladding.

In this paper, in order to improve microhardness and wear resistance of grinding layers for metal-bonded laser cladding grinding tools, the integrity of CBN grits during laser cladding process is protected and bonding quality between metal matrix and CBN grits is improved. 0%, 1.25%, 2.5%, 3.75%, and 5% of B 4 C as additive for CBN/CuSnTi laser cladding layers were conducted. The surface morphology of these laser cladding layers was observed. The elements distribution and species of phases in cross section of these laser cladding layers were analyzed by scanning electron microscopy (SEM)/energy dispersive spectrometer (EDS) and X-ray diffractometer (XRD), and reaction mechanism was analyzed by Gibbs free energy theory. The microhardness and wear resistance of these laser cladding layers were tested. Then, grinding tests with 0%, 2.5%, and 5% B 4 C added CBN/CuSnTi LCGTs were conducted. The results show that no cracks and intact CBN cutting edges were on laser cladding layer when 5% B 4 C was added. The mechanical quality involved microhardness and wear resistance of 5% B 4 C added laser cladding layer were better than that of other B 4 C contents of laser cladding layers. The surface roughness of 5% added LCGT is the best. 5% B 4 C can be the additive for CBN/CuSnTi LCGT.

To reduce deposition defects (cracks and porosity) of the ceramics reinforced Fe-based coatings, and improve their microstructure uniformity, microhardness, and wear resistance, different content of CeO 2 (0, 1.0, 2.0, 2.5, and 3.0 wt.%) was added to the Fe-based powders. The effects of CeO 2 addition on the microstructure, phase composition, and mechanical properties were investigated by an optical microscope, X-ray diffraction (XRD), scanning electron microscopy (SEM), Vickers hardness tester, and friction wear tester. The results show that appropriate CeO 2 addition not only can reduce the cracks and porosities but also improve the bonding performance between the composite coating and the substrate. The study also finds that the addition of CeO 2 promotes the melting of large-size ceramic particles, increases the nucleation sites, and further refines the microstructure. The mechanical properties of each coating show that the microhardness and wear resistance firstly increases and then decreases with the increase of CeO 2 addition. The ceramics reinforced Fe-based coatings with 2.5 wt.% CeO 2 addition exhibites the highest and most uniform microhardness, and the smoothest worn surface despite the higher friction coefficient. Thus, CeO 2 addition is an effective method to refine the microstructure, reduce cracks and porosities in the TiN and Ti (C, N) reinforced Fe-based coating, and further improve microhardness and wear performance.

During the laser cladding process for composite coatings, significant differences exist in the physical and mechanical properties between the substrate and the composite coating materials. Therefore, a systematic analysis of the mechanical properties is necessary to mitigate issues such as cracking and deformation caused by performance mismatch. This study investigated the mechanical properties (microhardness, wear resistance, tensile strength) of composite coatings formed by laser cladding IN718 alloy onto an EA4T steel substrate. Given the critical influence of scanning strategies on cladding layer quality, this study also examined the relationship between the tensile direction and scanning direction. By analyzing mechanical responses under different orientations, it revealed the patterns of influence on tensile properties and anisotropy characteristics of the cladding layer, providing a theoretical basis and process guidance for achieving high-performance cladding layers. Tensile tests conducted at different angles on the IN718 cladding layer indicate that when a thin cladding layer is required, selecting a scanning speed direction parallel to the primary tensile direction yields superior results. Conversely, for applications demanding a thicker cladding layer, aligning the scanning direction perpendicular to the tensile direction better leverages the cladding layer's performance.

Laser cladding offers distinct advantages over traditional manufacturing methods, including low heat input, minimal dilution ratio, dense clad layers, and robust bonding. It is widely employed for surface strengthening of metals to enhance performance and repair failed components, thereby reducing material waste. This study investigates laser cladding repair of EA4T steel, focusing on examining the effects of laser power, scanning speed, and powder feed rate on melt pool dilution ratio and shape factor during cladding of IN718 material onto EA4T steel substrate. Orthogonal experiments were conducted to investigate the combined effects of different process parameters on dilution rate and shape factor. Optimal process parameters were determined by comprehensively evaluating melt pool cross-sectional morphology and internal defects. Based on this, theoretical lap calculations were performed, and the optimal theoretical lap ratio was obtained through experiments. Experiments indicated that the influence of process parameter variations on molten pool morphology parameters is not linear; the combined effects of all factors must be comprehensively considered.

To eliminate the negative effect of traditional metal-working fluids and achieve sustainable manufacturing, the usage of nano-enhanced biolubricant (NEBL) is widely researched in minimum quantify lubrication (MQL) machining. It’s improved tool wear and surface integrity have been preliminarily verified by experimental studies. The previous review papers also concluded the major influencing factors of processability including nano-enhancer and lubricant types, NEBL concentration, micro droplet size, and so on. Nevertheless, the complex action of NEBL, from preparation, atomization, infiltration to heat transfer and anti-friction, is indistinct which limits preparation of process specifications and popularity in factories. Especially in the complex machining process, in-depth understanding is difficult and meaningful. To fill this gap, this paper concentrates on the comprehensive quantitative assessment of processability based on tribological, thermal, and machined surface quality aspects for NEBL application in turning, milling, and grinding. Then it attempts to answer mechanisms systematically considering multi-factor influence of molecular structure, physicochemical properties, concentration, and dispersion. Firstly, this paper reveals advanced lubrication and heat transfer mechanisms of NEBL by quantitative comparison with biolubricant-based MQL machining. Secondly, the distinctive filmformation, atomization, and infiltration mechanisms of NEBL, as distinguished from metal-working fluid, are clarified combining with its unique molecular structure and physical properties. Furtherly, the process optimization strategy is concluded based on the synergistic relationship analysis among process variables, physicochemical properties, machining mechanisms, and performance of NEBL. Finally, the future development directions are put forward aiming at current performance limitations of NEBL, which requires improvement on preparation and jet methods respects. This paper will help scientists deeply understand effective mechanism, formulate process specifications, and find future development trend of this technology.

Structured CBN (cubic boron nitride) grinding wheels usually have a specially designed texture on their surface to reduce the grinding heat and grinding force. However, most structured grinding wheels are fabricated by electroplating, brazing, sintering, and mechanical or laser removal on the surface of conventional grinding wheels, which may have problems such as complicated processes, low processing efficiency, and unstable effects. In this paper, additive manufacturing was used to fabricate a radial straight groove-structured grinding wheel. Meanwhile, a corresponding mathematical model of the grinding wheel was also established considering the shape and position of the abrasive grains. Subsequently, the ground surface morphologies of the fabricated wheel and simulated wheel under different machining parameter conditions were compared to further prove the rationality of the simulated grinding wheel. The results showed that the ground surfaces of the fabricated wheel and simulated wheel had similar morphological characteristics. The trend in the surface roughness under the different machining parameter conditions was also analyzed and showed the same variation for fabricated and simulated wheels; the error rate was confined within 8%. This paper elucidates the grinding mechanism and surface morphology formation process of a radial straight groove-structured grinding wheel fabricated by additive manufacturing.

Direct laser fabrication (DLF) known as the additive manufacturing technology was employed in this paper; the optimal methods of generating thin-walled cylinders were researched. The building accuracy was analyzed via employing three main optimal strategies, scanning strategy (S), laser power adjustment (L) and Helical scanning optimization (H), and their interaction effects (SL, LH, HS, SHL). In addition, synclastic scanning strategy (method 1), reversed scanning strategy (method 2), and new collative variable of Z-axis increment (method 3) combining with those optimal tactics were verified by fewer defections and greater performance. As a result, method 1SHL and method 2SL are proven to be the best method to optimize the process to fabricate thin-walled cylinders.

With the development of science and technology, many precision fields have higher requirements for the machining quality and precision of hard and brittle materials. Brittle materials such as glass and ceramics have fragile physical properties, resulting in poor stability during machining. Ultrasonic vibration-assisted polishing (UVAP) is suitable for machining various brittle materials and can well solve the machining problems caused by the characteristics of brittle materials. In order to ensure the machining quality, a polishing force model of K9 optical glass for different processing parameters is established in this paper. The new model mainly considers the following aspects: (1) Considering the randomness of shape, the truncated polyhedral model is used to model the abrasive particles. (2) Based on the fractal theory and mathematical statistics, a microscopic morphology model of the polishing tool is established. (3) Based on the N–S equation, a polishing force model considering the micro-contact states of the polishing tool, abrasive particles, and workpiece is established. By comparing with the experimental results, the new model has high accuracy in predicting the polishing force. The new model and results lay the foundation for the subsequent research of brittle materials.

As an advanced additive manufacturing technology, laser cladding has become a research hotspot in the fields of rapid manufacturing and surface modification in recent years. The quality of the cladding layer directly depends on the choice of process parameters. In order to obtain high quality cladding layer, the effects of laser power, scanning speed, and powder feeding rate on the quality of JG-3 iron-based powder cladding layer were studied by interaction orthogonal experiments. Three-dimensional measurement laser microscopy (3D MLM) and variance analysis were used to analyze the results. It was found that the interaction between laser power and powder feeding rate directly affects the optimum process parameters. Laser power 750 W, scanning speed 420 mm/min, and powder feeding rate 6.96 g/min were selected as the optimum process parameters. Scanning electron microscope (SEM), X-ray diffraction (XRD), and Thermo-Calc software were used to analyze the microstructure, phase composition, and solidification process of the coating, and compared with the experimental results. The results show that under the optimum process parameters, a dense crack-free and non-porous coating was obtained. The coating can be divided into three areas: coating zone (CZ), bonding zone (BZ), and heat affected zone (HAZ). The CZ is composed of α -Fe, Cr 2 B, Fe 2 B, and Cr 23 C 6 phases. The calculated results obtained from the Thermo-Calc software are in good agreement with the experimental data. It is beneficial to the coating design for a desirable microstructure and mechanical properties.