Effect of ultrarapid cooling on microstructure of laser cladding IN718 coating

Zhang, Y. C.; Li, Zhuguo; Nie, Pulin; Wu, Yixiong

doi:10.1179/1743294413y.0000000142

Cited by 74 publications

(28 citation statements)

References 12 publications

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“…The quantitative relationship between the different substrate temperature and temperature gradient can be expressed by the formula [ 53 ]

where G is the temperature gradient between the substrate and the cladding layer, T is the liquidus temperature of the IN718 alloy, T 0 is the preheating temperature of the substrate,

is the laser absorption rate, P and K are the laser power and the thermal conductivity of the material, respectively. Hunt et al [ 54 ] researched and proposed the columnar-to-equiaxed transition model, changing different cooling methods to affect the dendrite distribution and dendrite segregation [ 55 , 56 , 57 ], which affect the porosities. It is of great benefit to understand the formation and distribution of porosities under different solidification conditions.…”

Section: Resultsmentioning

confidence: 99%

Investigation on the Microporosity Formation of IN718 Alloy during Laser Cladding Based on Cellular Automaton

et al. 2021

Materials

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Porosity is one of the most common defects in the laser cladding of Inconel 718 (IN718) alloy, which can reduce the strength and fatigue performance of the components. However, the dynamic formation of microporosity is challenging to observe through experiments directly. In order to explore the formation mechanism of porosities and dynamically reproduce the competitive growth between porosities and dendrite, a multi-scale numerical model was adopted, combined with a cellular automaton (CA) and finite element method (FEM). The decentered square algorithm was adopted to eliminate crystallographic anisotropy and simulate dendrite growth in different orientations. Afterward, based on the formation mechanism of microporosity during solidification, equiaxed and columnar dendrites with porosities were simulated, respectively. Dendrite morphology, porosity morphology, and distribution of solute concentration were obtained during the solidification process. The simulation results were reasonably compared with experimental data. The simulation results of the equiaxed crystal region are close to the experimental data, but the columnar crystal region has a relative error. Finally, the interaction effects of porosities and dendrites under different environmental conditions were discussed. The results suggested that with the increase in the cooling rate, the quantity of porosity nucleation increased and the porosity decreased.

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“…The quantitative relationship between the different substrate temperature and temperature gradient can be expressed by the formula [ 53 ]

where G is the temperature gradient between the substrate and the cladding layer, T is the liquidus temperature of the IN718 alloy, T 0 is the preheating temperature of the substrate,

Section: Resultsmentioning

confidence: 99%

Investigation on the Microporosity Formation of IN718 Alloy during Laser Cladding Based on Cellular Automaton

et al. 2021

Materials

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“…In addition, the Vickers hardness of the vanadium-added alloy is higher than that of the No. 1 alloy of the blank sample, which is due to the influence of the distribution of the Laves phase [ 33 , 34 , 35 , 36 ]. However, the hardness of the alloy with vanadium added is not an evident trend in different locations, so the most appropriate content of the vanadium element cannot be obtained.…”

Section: Resultsmentioning

confidence: 99%

Effect of Vanadium Content on the Microstructure and Mechanical Properties of IN718 Alloy by Laser Cladding

Xu-dong

et al. 2021

Materials

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Microalloying vanadium can change the segregation state of Nb element in IN718 alloy, reduce the formation of harmful Laves phase and refine the dendritic structure of IN718 alloy during the laser process. Therefore, IN718 alloys with V content from 0.081 to 1.88 wt.% were prepared and evaluated. Metallographic microscopy and scanning electron microscopy were used to observe the corresponding morphology, structure, and distribution of elements. First of all, it was found that the addition of V refines the grain size of IN718 alloy and reduces the primary dendrite arm spacing. Secondly, adding V to IN718 alloy can reduce the porosity of the cladding layer. The elements are uniformly distributed in the cladding layer, and the addition of vanadium reduces the segregation degree of the Nb element, which is conducive to homogenization. In addition, microhardness and residual stress were also investigated. Finally, the addition of vanadium was shown to have no apparent effect on the tensile strength and yield strength but can significantly improve the elongation of IN718 alloy. In conclusion, the microstructure and mechanical properties of IN718 alloy with 0.081 wt.% vanadium content provide a new solution to improve the application level of IN718 alloy in laser cladding.

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“…We concluded that with the addition of V, the average micro hardness of the sample increased by 9.5%. According to previous studies [24,25], the Laves phase morphology and volume fraction are the main factors affecting the micro hardness of IN718 alloy. Our comparison of the average micro hardness between No.1 and No.2 alloy supports this finding.…”

Section: Resultsmentioning

confidence: 99%

Influence of Vanadium on the Microstructure of IN718 Alloy by Laser Cladding

et al. 2019

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A deleterious Laves phase forms in the solidified structure of Inconel 718 (IN718) alloy during laser cladding. However, effective removal methods have not yet been identified. In this study, we first added the IN718 alloy cladding layers with a trace amount of vanadium (V, 0.066 wt.%). Then, we studied the solidification structure of cladding layers using a confocal laser scanning microscope and scanning electron microscopy. The microstructure and Laves phase morphology were investigated. The distribution of niobium (Nb) was observed by experiment as well. We found that V is evenly distributed in dendrites and interdendritic zones. A more refined dendrite structure, reduced second dendrite arm spacing and lower volume fraction of Laves phase were observed in the solidification structure. The results of linear energy-dispersive X-ray spectroscopy (EDS) indicate that the concentration of Nb decreases with an increasing of the distance from the Laves phase. The V-containing sample displayed a relatively slower decreasing tendency. The IN718 alloy sample was harder with the addition of V. In addition, the porosity of the sample decreased compared with the blank sample. The presented findings outline a new method to inhibit the Nb segregation in IN718 alloy during laser cladding, providing reference significance for improving the performance of IN718 alloy samples during actual processing.

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Effect of ultrarapid cooling on microstructure of laser cladding IN718 coating

Cited by 74 publications

References 12 publications

Investigation on the Microporosity Formation of IN718 Alloy during Laser Cladding Based on Cellular Automaton

Investigation on the Microporosity Formation of IN718 Alloy during Laser Cladding Based on Cellular Automaton

Effect of Vanadium Content on the Microstructure and Mechanical Properties of IN718 Alloy by Laser Cladding

Influence of Vanadium on the Microstructure of IN718 Alloy by Laser Cladding

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