Building the analytical model between process parameter and results is the prerequisite for explaining the complex process of laser cladding “laser-powder” interaction, as well as the critical ...guidance for processing conduction, prediction, and control of geometrical characteristics. This paper utilized response surface methodology (RSM) to study the effect on multi-track cladding width, flatness ratio, and dilution among the following major process parameters: laser power (LP), scanning speed (SS), gas flow (GF), and overlapping rate (OR). The experiment was based on four factors and five levels designed to build the model between processing parameters as input and processing results as output by RSM multiple regression analysis. Variance analysis and significant test was utilized to validate the model. By predicting the geometrical characteristics to optimize processing parameters, get the multi-track cladding layer with the maximum width, the minimum flatness ratio, and dilution. The predictive value and experiment results had a difference of 4.17, 3.68, and 3.56%, for width, flatness ratio, and dilution respectively, which provided another validation for this model. The model could be used on controlling of multi-tracking cladding geometrical characteristics, prediction of performance, and optimization of process parameters.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This study aims at improving the coating properties and cladding efficiency in composite material laser cladding. Using Taguchi orthogonal experimental design, the correlation between processing ...parameters and index of cladding quality had been investigated. By altering the input of laser power, scanning speed, gas flow, and tungsten carbide powder ratio in laser cladding setup, their influence on the micro-hardness and wear resistance of the clad as well as the cladding efficiency had been studied. This study achieved processing parameter optimization with grey relational analysis by combining multiple objectives. Results showed that the micro-hardness and wear resistance of the clad were significantly affected by the WC powder ratio in the composite. Also, the laser power denoted a significant impact on the cladding efficiency. To obtain the clad with maximum micro-hardness and minimum wear volume while also attaining the maximum cladding efficiency, grey relational analysis was utilized to combine these multiple objectives in optimization. The processing parameter set obtained from optimization met the targets and showed a small-scale error rate of 4.92% in the grey relational grade prediction. This study verified the applicability and provided the theoretical basis for multiple-objective optimization of the coating properties and cladding efficiency in composite laser cladding.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This research investigated the influence of different processing parameters in curved surface multi-track laser cladding with curve paths. Mathematical models of flatness ratio, incomplete fusion, ...and pore area in the clad were developed by central composite design with altering the input laser power, scanning speed, gas flow, and overlapping rate. Response surface methodology was used to analyze the correlation of different processing parameters affecting the selected responses. A clad with better flatness ratio was achieved by properly increasing the laser power and gas flow while reducing the overlapping rate. Appropriately increasing the laser power and overlapping rate while reducing the scanning speed and gas flow effectively diminished the incomplete fusion. Less pore area in the clad was obtained by appropriately increasing the laser power and overlapping rate while reducing the scanning speed and gas flow. Afterwards, desired processing parameters set was obtained by the optimization with the target of maximizing the flatness ratio and also minimizing the incomplete fusion and pore area. Experimental validation with this processing parameter setup provided satisfactory clad, and the error rate for the flatness ratio, incomplete fusion, and pore area was 1.708%, 5.714%, and 6.522%, respectively. This paper provides the theoretical guidance for the prediction and control of the flatness ratio, incomplete fusion, and pore area in curved surface multi-track laser cladding with curve paths.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this research, the TiC–Ni35A composite coating was fabricated on the AISI 1045 steel substrate by laser cladding process. The cross-sectional morphology, microstructure, microhardness, and wear ...resistance of coatings obtained under different laser energy densities (E) and TiC powder ratios (PR) were analyzed. According to the results, all the coating had a reliable metallurgical bonding with the AISI 1045 steel substrate. The X-ray diffraction (XRD) analysis revealed that the coating phases were Ni and TiC. The average microhardness of the Ni35A-80wt.% TiC coating reached up to 75.1 HRC. The minimum coefficient of friction of the composite coating was only about 30% of the AISI 1045 steel substrate. The wear form was mainly adhesive wear when altering the TiC powder ratios, while the wear form also contained abrasion wear under different energy densities. The ability of decomposition and re-nucleation of TiC was significantly improved with the increase of laser energy densities and the decrease of TiC powder ratios. The microhardness, wear resistance, and coefficient of friction of the composite coating were improved because of the TiC strengthening phase particles. Compared with the AISI 1045 steel substrate, the microhardness and wear resistance of the composite coating were increased by 5.3 times and 6.3 times, respectively.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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•Mo2FeB2/WC self-lubricating coatings were fabricated via laser cladding.•Microstructure of Mo2FeB2/WC coating was refined by the addition of h-BN.•Tribological properties of ...Mo2FeB2/WC self-lubricating coatings were revealed.
To enhance the tribological properties and service life of Mo2FeB2/WC coatings, self-lubricating composite coatings with addition of WS2, MoS2, and h-BN were fabricated using laser cladding. The morphology, microstructure, microhardness, and tribological properties of the Mo2FeB2/WC self-lubricating composite coatings were investigated. The results indicated that the addition of WS2, MoS2, and h-BN increased the bonding properties between the coating and substrate. Sulfides and nitrides were found in the self-lubricating composite coatings; the Mo2FeB2/WC/h-BN coating exhibited a fine dendritic structure. The microhardnesses of the Mo2FeB2/WC, Mo2FeB2/WC/WS2, Mo2FeB2/WC/MoS2, and Mo2FeB2/WC/h-BN coatings were 1591.3 HV0.5, 1345.6 HV0.5, 1378.9 HV0.5, and 1415.3 HV0.5, respectively. After the addition of WS2, MoS2, and h-BN, the coefficients of friction decreased by 9.09%, 15.15%, and 30.30%, respectively; the corresponding wear rates decreased by 10.80%, 19.03%, and 30.97%, respectively. The self-lubricating phases significantly improved the tribological properties of the Mo2FeB2/WC coating. The main wear mechanisms of the Mo2FeB2/WC coating were adhesive and mild oxidative wear; the wear mechanisms after the addition of WS2, MoS2, and h-BN were abrasive and oxidative wear. The wear debris was powder-like for the Mo2FeB2/WC/WS2 and Mo2FeB2/WC/MoS2 coatings and flake-like for the Mo2FeB2/WC/h-BN coating. The lubricating transfer film caused an improvement in the tribological properties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
WCoB-TiC composite coatings with in-situ formation of NbC were fabricated on the surface of an AISI 1045 substrate by laser cladding. The geometric characteristics, microstructure, microhardness, and ...fracture toughness of coatings were investigated by means of an optical microscope (OM), a scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), an electron probe microanalyzer (EPMA), and a microhardness tester. In addition, the elastic constants and bulk property of the reinforced phases were investigated by first principles calculation. The results showed that a reliable metallurgical bonding was formed between the coating and the substrate and in-situ synthesized reinforcement phases of the coating consisted of WCoB, W
2
CoB
2
, TiC, NbC, (Nb,Ti,W)C, and traces of Nb
2
C. The dilution rate and porosity had a negative effect with the addition of Nb. According to the results of SEM, EDS, and EPMA, Nb was diffused uniformly in the TiC structure. The NbC phase had the highest hardness among all in-situ synthesized reinforcement phases, which reached 24.525 GPa, while Nb
2
C reflected the strongest metallicity. The microhardness and fracture toughness of the coating were increased firstly and then decreased following the increase of Nb content, and when the Nb addition was 4 wt%, the coating had the highest average microhardness and fracture toughness (1755.42 HV
0.5
, 8.23 MPa·m
1/2
, respectively). The microhardness and fracture toughness was 24% and 30% higher than that of the coating without Nb addition, respectively. From the crack propagation morphology of coatings, all coatings had fine transgranular fracture.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The optimal process parameters of ultrasonic-assisted processing were studied to further improve the molding quality and mechanical properties of Ni60/WC-TiO2+La2O3 composite coating. A single-factor ...experiment was used to explore the influences of ultrasonic vibration frequencies on Ni60/WC-TiO2+La2O3 composite coating. The microstructure, elemental composition, phase composition, hardness, and wear resistance of the coating were studied using scanning electron microscopy (SEM), an X-ray diffractometer (XRD), an energy spectrometer, a microhardness meter, a friction and wear tester, and other equipment. Ultrasonic vibrations significantly improved the problems of pores in the coating, and the porosity was reduced from 0.13 to 0.014%. When the vibration frequency was 32 kHz in the experiment, the aspect ratio of the coating was optimized from 2.06 to 2.48, the dilution rate increased from 5.60 to 5.79%, the hardness increased from 960.25 to 988.45 HZ1.0, and the friction coefficient was reduced from 0.34 to 0.27. The coating performance was significantly improved, and the research results provide a reference for preparing excellent Ni60/WC-TiC+La2O3 composite coating.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This paper investigates the effects of welding voltage, welding current, wire feeding speed, travelling speed and welding position on aspect ratio, dilution rate, microhardness and fluctuation using ...orthogonal experiment design. To achieve multi-objective optimization, S/N ratio conversion and grey relational analysis were employed, The model-predicted process parameters were then verified. The study findings indicate that the welding position has the greatest impact on aspect ratio, dilution rate and fluctuation, while the welding current has the greatest impact on the microhardness. Additionally, the force of the droplets at different positions affects the average aspect ratio and fluctuation, the arc shape affects the dilution rate, and the heat input affects the microhardness. Furthermore, the arc shape at different positions exhibits distinct characteristics. Finally, the optimal process parameters for different positions were obtained through an orthogonal test. The optimal combination of process parameters was found to be 70 A for welding current, 25 V for welding voltage, 500 cm
.
min
−1
for wire feeding speed, 50 cm
.
min
−1
for travelling speed, and vertical up welding position. The experimental results indicate that the optimized process parameters can consistently improve the welding quality, with a relative error of only 2.38% of only 2.38% between the grey relational degree and predicted value. This study's findings hold significant practical value for enhancing welding process stability and quality.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper aims at optimizing the surface hardness and wear resistance of composite coatings. The influence of Ni35A proportions in the composite mixing with TiC, WC, and W6Mo5Cr4V2 were explored ...based on mixed-level orthogonal experiment design. Experiments were conducted to examine the hardness and friction. The worn morphology was analysed by the white light interferometer. The multi-response optimization was achieved by the grey correlation analysis. The results show that both the powder ratio and powder type had significant impact on the micro-hardness and wear volume of the coatings, where powder ratio has more significance. Finally, the multi-index optimization was conducted with the target of maximizing the micro-hardness and minimizing the wear volume simultaneously by combining grey relational analysis and orthogonal experiment. The error rate is 1.122% between the prediction and experimental validation. Compared with the substrate, the micro-hardness of optimized cladding layer was improved from 15.2 to 68.8 HRC, while the wear volume was reduced from 15.28257 to 1.04831·10
−3
mm
3
. The comparison of the optimal group in the orthogonal experiment indicates that the micro-hardness and wear resistance of optimized cladding layer were also improved. The optimized cladding layer has fine, dense, and evenly distributed grains with coarse and complete grain boundaries, suggesting that the micro-hardness and wear resistance were improved after optimization. The application of the mixed-level orthogonal experiment design combined with the grey correlation analysis allows to achieve the optimal selection of various hard-phase composite materials and the process optimization.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Mo
2
FeB
2
coatings were fabricated by laser cladding with different pre-placed powder sizes. In the present research, a coaxial nozzle head coupled with a continuous fiber laser with a maximum power ...of 3 kW was used. The influence of powder size (~ 6 μm, ~ 13 μm, ~ 65 μm) on the morphology, microstructure, microhardness, wear resistance, and fracture toughness of the coating were discussed in this research. The morphology showed that coating obtained with ~ 6-μm powder size had excellent wettability and avoided obvious defects; microstructure revealed that the coating appeared particle agglomeration phenomenon with the increase of powder size. The coating obtained with ~ 6 μm had herringbone and feature structures to improve the density, and the bonding zone had typical columnar crystal and no cracks. The microhardness, wear resistance, and fracture toughness decreased as the increase of powder size. The optimal microhardness, COF, and fracture toughness of coating reached 1138.56 HV
0.5
, 0.59, 14.65 MPa·m
1/2
, respectively, when powder size was ~ 6 μm. The wear form of coatings was typical abrasive wear and adhesive wear; the fracture mechanism was transgranular fracture. The research can provide a reference for the preparation of Mo
2
FeB
2
ternary boride coating.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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