Direct laser metal deposition of René 108 single crystal superalloy

Sreeramagiri, Praveen; Bhagavatam, Ajay; Alrehaili, Husam; Dinda, G.P.

doi:10.1016/j.jallcom.2020.155634

Cited by 20 publications

(6 citation statements)

References 18 publications

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“…The solidification rate is zero at the bottom of the weld pool, but it will increase up to a constant value closer to the surface. Meanwhile, the maximum thermal gradient takes place at the bottom of the pool and decreases rapidly toward the surface until being fixed at a constant value, owing to the heat sink effect from the prior layers and the BM [ 61 ]. Two other essential solidification parameters can be defined based on these known parameters, namely stability criterion and cooling rate, which affect the interface morphology and the microstructure size, respectively [ 13 , 62 ].…”

Section: Resultsmentioning

confidence: 99%

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Effect of Laser Metal Deposition Parameters on the Characteristics of Stellite 6 Deposited Layers on Precipitation-Hardened Stainless Steel

et al. 2021

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Laser metal deposition (LMD) is one of the manufacturing processes in the industries, which is used to enhance the properties of components besides producing and repairing important engineering components. In this study, Stellite 6 was deposited on precipitation-hardened martensitic stainless steel (17-4 PH) by using the LMD process, which employed a pulsed Nd:YAG laser. To realize a favor deposited sample, the effects of three LMD parameters (focal length, scanning speed, and frequency) were investigated, as well as microstructure studies and the results of a microhardness test. Some cracks were observed in the deposited layers with a low scanning speed, which were eliminated by an augment of the scanning speed. Furthermore, some defects were found in the deposited layers with a high scanning speed and a low frequency, which can be related to the insufficient laser energy density and a low overlapping factor. Moreover, various morphologies were observed within the microstructure of the samples, which can be attributed to the differences in the stability criterion and cooling rate across the layer. In the long run, a defect-free sample (S-120-5.5-25) possessing suitable geometrical attributes (wetting angle of 57° and dilution of 25.1%) and a better microhardness property at the surface (≈335 Hv) has been introduced as a desirable LMDed sample.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Effect of Laser Metal Deposition Parameters on the Characteristics of Stellite 6 Deposited Layers on Precipitation-Hardened Stainless Steel

et al. 2021

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“…Post nucleation, grains grow in the direction opposite to the heat transfer driven by the thermal gradient ( G ) and the solidification rate ( R ) [ 149 ]. A high G / R ratio advocates the formation of columnar growth, noted in the melt-pool core, while a reduced G / R favors equiaxed grains at the top of the melt pool, as displayed in Figure 7 [ 150 ]. The cooling rate is defined as G × R and is responsible for grain size, suggesting finer grains are observed for higher cooling rates [ 62 ].…”

Section: Computational Approachesmentioning

confidence: 99%

Advances and Challenges in Predictive Modeling for Additive Manufacturing of Dissimilar Metals and Complex Alloys

Adak,

Sreeramagiri,

Roy

et al. 2023

Materials

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We present a scrutiny on the state of the art and applicability of predictive methods for additive manufacturing (AM) of metals, alloys, and compositionally complex metallic materials, to provide insights from the computational models for AM process optimization. Our work emphasizes the importance of manufacturing parameters on the thermal profiles evinced during processing, and the fundamental insights offered by the models used to simulate metal AM mechanisms. We discuss the methods and assumptions necessary for an educated tradeoff between the efficacy and accuracy of the computational approaches that incorporate multi-physics required to mimic the associated fluid flow phenomena as well as the resulting microstructures. Finally, the current challenges in the existing approaches are summarized and future scopes identified.

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“…Moreover, the solidification velocity in the center area is 5.3 times that of the overlap area. Compared with the laser cladding (10 2 -10 6 K/s) [7,35] and electro-spark deposition (10 5 -10 6 K/s) [36], the cooling rate in electron beam cladding technology is between that of the ESD and the laser cladding technology. For cooling rate ε = V × G [11], the cooling rate of the four regions (the bottom, middle, center area and overlapping area of the coating) are calculated as 2.6 × 10 5 K/s, 1.3 × 10 5 K/s, 8.5 × 10 4 K/s and 1.6 × 10 4 K/s, respectively, as shown in Figure 8.…”

Section: Characterization Of the Deposited Coatingmentioning

confidence: 99%

Microstructure Evolution of CET-Free Epitaxial Growth NiCoCrAlYTa Coating by Electron Beam Cladding

et al. 2023

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Some unavoidable factors in the operating environment could damage single-crystal components of nickel-based single-crystal superalloys. This work prepared an epitaxial growth NiCoCrAlYTa repaired coating without the columnar-to-equiaxed transition (CET) phenomenon on a nickel-based single-crystal superalloy by electron beam cladding. The microstructure of two cross-sections and two surfaces at different depths were characterized. Moreover, the formation mechanism of coating dendrite was revealed by studying the relationship between coating dendrite size, growth direction, and solidification rate. The microstructure evolution and crystal growth orientation of the coating were investigated. The microstructural investigation of the sample revealed that the dendrites’ orientations on the coating’s horizontal section were different, and its characteristics were highly visible on the surface of the coating. The crystal growth orientations of the coating on the vertical cross-section parallel/perpendicular to the scanning direction of the electron beam were also different. Moreover, the average primary dendrite arm spacing (PDAS) of the columnar dendrite in the different areas of the coating was different and increased from 2 μm to 4 μm. The oxidation resistance of the coating at 1000 °C was about three times higher than that of the substrate.

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Direct laser metal deposition of René 108 single crystal superalloy

Cited by 20 publications

References 18 publications

Effect of Laser Metal Deposition Parameters on the Characteristics of Stellite 6 Deposited Layers on Precipitation-Hardened Stainless Steel

Effect of Laser Metal Deposition Parameters on the Characteristics of Stellite 6 Deposited Layers on Precipitation-Hardened Stainless Steel

Advances and Challenges in Predictive Modeling for Additive Manufacturing of Dissimilar Metals and Complex Alloys

Microstructure Evolution of CET-Free Epitaxial Growth NiCoCrAlYTa Coating by Electron Beam Cladding

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