Effect of Solution-Treatment on Microstructure and Mechanical Properties of Cast Fine-Grain CM 247 LC Superalloy

Huang, Hsin-Erh; Koo, Chun-Hao

doi:10.2320/matertrans.45.1360

Cited by 23 publications

(5 citation statements)

References 13 publications

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“…The microstructure contains three distinct morphologies of γʹ precipitates: (i) irregularly shaped γʹ precipitates, 1-2 µm in size, predominantly located at the boundaries of the recrystallised grains and cell colonies; (ii) smaller cuboidal precipitates, 200-500 nm in size, uniformly distributed within the recrystallised grains; (iii) small precipitates of a similar size but more irregular morphology, uniformly distributed within the unrecrystallised grains. The morphology of the intragranular γʹ precipitates in the recrystallised grains was similar to that previously reported for conventionally cast CM247LC[28]. In addition, carbide particles were identified, ranging from 200 to 500 nm in size.…”

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confidence: 83%

Microstructure of selective laser melted CM247LC nickel-based superalloy and its evolution through heat treatment

Divya

Muñoz‐Moreno

Messé

et al. 2016

Materials Characterization

214

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The selective laser melting of high temperature alloys is of great interest to the aerospace industry as it offers the prospect of producing more complex geometries than can be achieved with other manufacturing methods. In this study, the microstructure of the nickelbased superalloy, CM247LC, has been characterised following selective laser melting and after a post deposition heat-treatment below the γʹ solvus temperature. In the as-deposited state, scanning electron microscopy with electron backscatter diffraction revealed a fine, cellular microstructure with preferential alignment of <100> along the build direction. A high dislocation density was seen at the periphery of the cells, indicating substantial localised deformation of the material. Fine primary MC carbides were also observed in the inter-cellular regions. High-resolution transmission electron microscopy identified the occurrence of very fine γʹ precipitates, approximately 5 nm in diameter, dispersed within the gamma phase. After heat treatment, the elongated cell colonies were observed to partially coalesce, accompanied by a decrease in dislocation density, producing columnar grains along the build direction. Cuboidal γʹ precipitates approximately 500 nm in diameter were observed to form in the recrystallised grains, accompanied by larger γʹ precipitates on the grain boundaries.

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supporting

confidence: 83%

Microstructure of selective laser melted CM247LC nickel-based superalloy and its evolution through heat treatment

Divya

Muñoz‐Moreno

Messé

et al. 2016

Materials Characterization

214

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“…The EDS results showed that SHT material contained large congregations of γ’-forming elements that are not present in the HSHT material. It is assumed that, by forming as segregates, these elements are not contributing to the precipitation of γ’ during the ageing treatment; therefore, the alloy deviates from the design volume-fraction, size and morphology of γ’ precipitates, all of which directly affect mechanical response [ 16 , 32 ]. The HSHT material does not visibly contain these segregates, suggesting that the heat treatment has fully solutionised these elements, allowing them to contribute to the forming of γ’ precipitates, increasing the γ’ volume fraction, resulting in an increased yield and UTS at the expense of a reduction in elongation or ductility [ 33 ].…”

Section: Discussionmentioning

confidence: 99%

High Temperature Deformation Mechanisms in a DLD Nickel Superalloy

et al. 2017

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The realisation of employing Additive Layer Manufacturing (ALM) technologies to produce components in the aerospace industry is significantly increasing. This can be attributed to their ability to offer the near-net shape fabrication of fully dense components with a high potential for geometrical optimisation, all of which contribute to subsequent reductions in material wastage and component weight. However, the influence of this manufacturing route on the properties of aerospace alloys must first be fully understood before being actively applied in-service. Specimens from the nickel superalloy C263 have been manufactured using Powder Bed Direct Laser Deposition (PB-DLD), each with unique post-processing conditions. These variables include two build orientations, vertical and horizontal, and two different heat treatments. The effects of build orientation and post-process heat treatments on the materials’ mechanical properties have been assessed with the Small Punch Tensile (SPT) test technique, a practical test method given the limited availability of PB-DLD consolidated material. SPT testing was also conducted on a cast C263 variant to compare with PB-DLD derivatives. At both room and elevated temperature conditions, differences in mechanical performances arose between each material variant. This was found to be instigated by microstructural variations exposed through microscopic and Energy Dispersive X-ray Spectroscopy (EDS) analysis. SPT results were also compared with available uniaxial tensile data in terms of SPT peak and yield load against uniaxial ultimate tensile and yield strength.

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“…has presented that the solutionising at temperature of 1155 °C/3 h and 1185 °C/3 h without temperature droppings shown fine γ΄ precipitates homogeneously distributed throughout the matrix. A multi-step solution treatment [8]. from 1221 °C/2 h to 1260 °C/2 h, was applied to as-cast CM 247LC Ni-based superalloy.…”

Section: Introductionmentioning

confidence: 99%

Effect of Double-Step Solution Treatment on Rejuvenation Heat Treated Microstructure of IN-738 Superalloy

Paa-Rai

2020

KEM

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This work investigates the effect of rejuvenation heat treatment, with double-step solution treatment at the temperature from 1150 °C to 1200 °C, on the recovered microstructure of IN-738 cast superalloy. The superalloy has been long-term exposed as a turbine blade in a gas turbine prior to this study. After double solution treatment and aging at 845 °C for 12 h and 24 h, the recovered microstructures were examined by using a scanning electron microscope. Coarse γ΄ particles, that have presented in damaged microstructures, could not be observed in the samples after the rejuvenation heat treatment. In addition, the image analysis illustrates that the reprecipitated γ΄ particles in the samples with double-step solution treatments increase significantly in sizes during aging than that in the samples with the single-step solution treatment. Furthermore, the measurement of the samples hardness presents that the as-receive sample hardness is improved after rejuvenation heat treatment studied in this work.

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Effect of Solution-Treatment on Microstructure and Mechanical Properties of Cast Fine-Grain CM 247 LC Superalloy

Cited by 23 publications

References 13 publications

Microstructure of selective laser melted CM247LC nickel-based superalloy and its evolution through heat treatment

Microstructure of selective laser melted CM247LC nickel-based superalloy and its evolution through heat treatment

High Temperature Deformation Mechanisms in a DLD Nickel Superalloy

Effect of Double-Step Solution Treatment on Rejuvenation Heat Treated Microstructure of IN-738 Superalloy

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