Thermomechanical analysis of multi-bead pulsed laser powder deposition of a nickel-based superalloy

Zhang, Chunbo; Li, Leijun; Deceuster, Andrew

doi:10.1016/j.jmatprotec.2011.03.023

Cited by 40 publications

(17 citation statements)

References 28 publications

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“…12,13 Most of this research focuses on either developing thermal models or characterizing microstructure and properties. [14][15][16][17][18][19][20] Recently, the role of heterogenous properties in Inconel 718 builds was pointed out by hardness mapping, electron backscatter diffraction imaging (EBSD), and electron microscopy. 5,21 Makiewicz characterized the effect of laser melted thermal build history for Inconel 718.…”

Section: B Application Of Am To Inconel 718mentioning

confidence: 99%

Thermal effects on microstructural heterogeneity of Inconel 718 materials fabricated by electron beam melting

et al. 2014

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Additive manufacturing technologies, also known as 3D printing, have demonstrated the potential to fabricate complex geometrical components, but the resulting microstructures and mechanical properties of these materials are not well understood due to unique and complex thermal cycles observed during processing. The electron beam melting (EBM) process is unique because the powder bed temperature can be elevated and maintained at temperatures over 1000°C for the duration of the process. This results in three specific stages of microstructural phase evolution: (a) rapid cool down from the melting temperature to the process temperature, (b) extended hold at the process temperature, and (c) slow cool down to the room temperature. In this work, the mechanisms for reported microstructural differences in EBM are rationalized for Inconel 718 based on measured thermal cycles, preliminary thermal modeling, and computational thermodynamics models. The relationship between processing parameters, solidification microstructure, interdendritic segregation, and phase precipitation (d, c9, and c0) are discussed.

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Section: B Application Of Am To Inconel 718mentioning

confidence: 99%

Thermal effects on microstructural heterogeneity of Inconel 718 materials fabricated by electron beam melting

et al. 2014

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“…Several authors have reported a limited precipitation of the γ′ phase due to the rapid cooling of the material following deposition [23,25,27] and as such will influence the heat treatment required to idealise the microstructure for functional use. The presence of residual stress in laser fabricated Ni-based superalloys poses a significant area of interest with studies being carried out into measurement [21,31] and modeling [32]. Previous work concerning a SLM powder-bed fabricated Ni-based superalloy has been carried out by Wu et al [33] which relates the parameters to dimensional accuracy, surface finish, density and cracking of Hastelloy X.…”

Section: Introductionmentioning

confidence: 99%

Laser Powder Bed Fabrication of Nickel-base Superalloys: Influence of Parameters; Characterisation, Quantification and Mitigation of Cracking

Carter¹,

Attallah²,

Reed³

2012

Superalloys 2012 (Twelfth International Symposium)

118

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The use of a selective laser melting (SLM) powder-bed method to manufacture Ni-based superalloys components provides an economic approach for low production run components that operate under a high-temperature and stress environment. A major concern with the SLM of precipitation hardenable Ni-based superalloys is their high susceptibility to cracking, which has been heavily documented in the field of welding. Weld cracking may occur either during processing (hot cracking, liquation cracking and ductility-dip cracking) or during the post weld heat-treatment stage (strain-age cracking). Due to the complex thermal history of SLM fabricated material there is the potential for all of these mechanisms to be active.In this investigation, cuboidal coupons of the Ni-based superalloy CM247LC were fabricated by the SLM of argon gas atomised powder. Parametric studies were performed to investigate the influence of the process parameters (laser scan speed, power and scan spacing) on the cracking density and morphology through conducting a stereological study of scanning electron microscope (SEM) micrographs. Further microstructural evidence is presented, illustrating the different crack morphologies observed as well as suggesting the responsible mechanisms. Finally a postfabrication Hot Isostatic Pressing (HIP) treatment was performed to investigate its utility in 'healing' the internal cracks, and providing a route to retro-fix the cracking problem in the heat treatment stage of production. The findings highlight the need for process models of the SLM method in order to understand the thermal history and the laser fabricated structures observed.

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“…The heat build-up causes the melt pool temperature to increase which in turn leads to lower deposit tracks, wider melt pools and more dilution. The effect of heat build-up in LMD is described by Zhang et al, [20]. It is therefore important, in order for LMD to be a reliable manufacturing method to control the heat build-up.…”

Section: Discussionmentioning

confidence: 99%

“…These elements include: aluminum, boron, carbon, chromium, cobalt, hafnium, iron, magnesium, manganese, molybdenum, niobium, rhenium, tantalum, titanium, tungsten, and zirconium [15]. A broad range of superalloys has been evaluated for LMD including Alloy-625 [13,[16][17][18][19][20], Alloy-718 [6,[21][22][23][24][25][26][27][28][29][30][31], Alloy-738 [12,32], CMSX4 [33][34][35], Rene41 [36,37] and Waspaloy [10,38]. There are some parameters of particular importance to LMD, as listed in Table 1, to have a controlled deposition.…”

Section: Materials Characteristics and Process Parametersmentioning

confidence: 99%

Review of Laser Deposited Superalloys Using Powder as an Additive

Segerstark¹,

Andersson²,

Svensson³

2014

8th International Symposium on Superalloy 718 and Derivatives (2014)

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In this paper laser metal deposition (LMD) with blown powder was reviewed with respect to the material behavior of nickel and nickel-iron based superalloys. The key benefits of LMD are claimed to be increased design freedom of components as well as reduced environmental impact since it enables near net shape manufacturing. This review considers the LMD processing parameters such as laser power, powder feed rate, spot size, standoff distance, and traverse speed, together with aspects related to the powder e.g. morphology, porosity, inclusion and satellite content. Special emphasis was put on how these parameters affect the deposit and substrate in terms of cracking, porosity, inclusions, phase transformations, and other material related phenomena. A characteristic microstructure of LMD deposited superalloys has a columnar dendrite growth in the vertical build up direction. The grain growth can however be manipulated, making it more equiaxed by, for instance, altering process parameters and/or scanning path. Residual stresses in LMD samples are unevenly distributed and large residual tensile stresses can be found at the surface of the deposit while large compressive stresses are located close to the substrate in the core of the deposit. One of the most important parameter is considered to be the specific energy input which largely influences the m elt pool during deposition which in turn can be related to the microstructure, residual stress and, process related defects such as porosity, cracking, lack of fusion and, dilution.

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Thermomechanical analysis of multi-bead pulsed laser powder deposition of a nickel-based superalloy

Cited by 40 publications

References 28 publications

Thermal effects on microstructural heterogeneity of Inconel 718 materials fabricated by electron beam melting

Thermal effects on microstructural heterogeneity of Inconel 718 materials fabricated by electron beam melting

Laser Powder Bed Fabrication of Nickel-base Superalloys: Influence of Parameters; Characterisation, Quantification and Mitigation of Cracking

Review of Laser Deposited Superalloys Using Powder as an Additive

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