Residual stress and crack initiation in laser clad composite layer with Co-based alloy and WC + NiCr

Lee, Changmin; Park, Hyungkwon; Yoo, Jung Ho; Lee, Changhee; Woo, Wanchuck; Park, Sunhong

doi:10.1016/j.apsusc.2015.03.168

Cited by 109 publications

(23 citation statements)

References 32 publications

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“…The dilution of the coating first decreases and then increases; different temperatures between the substrate and the cladding layer leads to the residual stress in the cladding layer first decreasing and then increasing. At the same time, while the coefficients of thermal expansion of the substrate and the cladding material are similar, the temperature of the cladding layer after solidification is higher than that of the substrate, so shrinkage of the cladding is larger than that of the substrate when cooled to normal temperature; the substrate is pressed and the cladding layer is pulled, resulting in the propagation of cracks [ 29 ].…”

Section: Resultsmentioning

confidence: 99%

Microstructures and Properties of Laser Cladding Al-TiC-CeO2 Composite Coatings

Dejun

Song

2018

Materials

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Al-TiC-CeO2 composite coatings have been prepared by using a laser cladding technique, and the microstructure and properties of the resulting composite coatings have been investigated using scanning electron microscopy (SEM), a 3D microscope system, X-ray diffraction (XRD), micro-hardness testing, X-ray stress measurements, friction and wear testing, and an electrochemical workstation. The results showed that an Al-Fe phase appears in the coatings under different applied laser powers and shows good metallurgical bonding with the matrix. The dilution rate of the coating first decreases and then increases with increasing laser power. The coating was transformed from massive and short rod-like structures into a fine granular structure, and the effect of fine grain strengthening is significant. The microhardness of the coatings first decreases and then increases with increasing laser power, and the maximum microhardness can reach 964.3 HV0.2. In addition, the residual stress of the coating surface was tensile stress, and crack size increases with increasing stress. When the laser power was 1.6 kW, the coating showed high corrosion resistance.

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Section: Resultsmentioning

confidence: 99%

Microstructures and Properties of Laser Cladding Al-TiC-CeO2 Composite Coatings

Dejun

Song

2018

Materials

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“…At present, Fe-based [1][2][3], Ni-based [4,5], and Co-based [6,7] self-fluxing alloy powders are widely used to repair and strengthen the surface performance in laser cladding. The mechanical properties of coatings are analyzed through microhardness, wear resistance and microstructure properties, and the results shows that coatings can be equal to, or even superior to those of the alloys fabricated by die-casting or forging [8,9].…”

Section: Introductionmentioning

confidence: 99%

Properties of Curved Parts Laser Cladding Based on Controlling Spot Size

Huang

2020

Applied Sciences

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In this study, a method based on controlling the laser spot size was proposed in the process of curved parts laser cladding, and the coatings obtained by this method were analysed through investigation of the microstructure, microhardness, adhesion property and wear resistance properties. The nonuniform rational B-spline surface (NURBS) reconstruction method was used to obtain the workpiece geometrical characteristics of laser cladding, and through the establishment of a mathematical model, the process of the laser beam working on the curved surface was simplified as the intersection of the cylinder and curvature sphere. Then, the spot size was transformed into the area of a cylinder intersecting with a sphere, and by adjusting the laser head, the size of the laser spot was controlled in the threshold and interpolation points were obtained. The laser cladding trajectory was ensured by these interpolation points, and the experiment was carried out to study the properties of the coating. The results showed that the average coating thickness was about 1.07 mm, and the fluctuation of coating thickness did not exceed 0.05 mm; also, there were no cracks or pores in the layer after penetrant flaw detection. The SEM showed that the grains passed through the transition of plane crystal, cellular crystal, dendrite and equiaxed crystal from the bottom to the top of the layer. After 30 cycles of thermal shock tests, the cladding layer was still well bonded with the substrate and the microhardness and wear resistance were 2 times and 1.4 times higher than that of substrate, respectively.

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“…If thermomechanical strains caused by the time-dependent temperature distribution during welding and material-specific shrinkage during the liquid-or solid-phase transition cannot be compensated for by the ductility of the weld metal or by reflow of the melt, solidification cracks will appear [7]. Furthermore, the residual stress caused by the changes in the chemical composition and the heating and cooling rates during the welding process can aggravate the initiation and growth of solidification cracks [8]. Measured residual stress data can be used for fracture analysis, safety design, and strength evaluations.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine‐Grained Steel

Liu

et al. 2018

Advances in Materials Science and Engineering

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Weld solidification crack prevention in the laser penetration welding process is essential for the strength of the welded component. The formation of solidification cracks can ultimately be attributed to welding residual stresses, and preventive measures should be taken during welding. In this study, the effects of residual stresses on the laser penetration welding quality of ultrafine-grained steels were investigated. A heat source model was established through the analysis of the metallography of the cross section of the heat-affected zone (HAZ) of ultrafine-grained AN420s-grade steel, and the chemical composition of the weld bead was obtained using an FLS980-stm Edinburgh fluorescence spectrometer. Furthermore, the constitutive coupling relation between the temperature and material flow stress was established based on the Gibbs function, and the welding residual stress was obtained by setting trace points in a finite element analysis (FEA) model based on experimental data of the weld bead cross section under different welding conditions. The results show that weld solidification cracks will form when the residual stresses exceed the material flow stresses in the weld bead, and the residual stresses can be decreased through a reasonable increase of the welding speed. The results indicate that the proposed criterion has high accuracy and can be used to predict the formation of weld solidification cracks in the laser penetration welding process.

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Residual stress and crack initiation in laser clad composite layer with Co-based alloy and WC + NiCr

Cited by 109 publications

References 32 publications

Microstructures and Properties of Laser Cladding Al-TiC-CeO2 Composite Coatings

Microstructures and Properties of Laser Cladding Al-TiC-CeO2 Composite Coatings

Properties of Curved Parts Laser Cladding Based on Controlling Spot Size

Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine‐Grained Steel

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