Effect of different heat treatments on the microstructure and mechanical properties in selective laser melted INCONEL 718 alloy

Raghavan, S.; Zhang, Baicheng; Wang, Pei; Sun, Chen-Nan; Nai, Mui Ling Sharon; Li, Tao; Wei, Jun

doi:10.1080/10426914.2016.1257805

Cited by 162 publications

(35 citation statements)

References 13 publications

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“…1). Nearly the same microstructure was interpreted as cellular and dendritic microstructure [12,13] observed in columnar grains [14,15,16]. SEM and TEM examination showed that the columnar subgrains in their turn consisted of equiaxed subgrains with a size of about 0.5 μm (Figs.…”

Section: Methodsmentioning

confidence: 89%

Nb rich precipitates in Inconel 718 produced by selective laser melting

Shakhov¹,

Mukhtarova²

2018

LoM

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Section: Methodsmentioning

confidence: 89%

Nb rich precipitates in Inconel 718 produced by selective laser melting

Shakhov¹,

Mukhtarova²

2018

LoM

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“…The XRD spectra for specimen #3 in as-built, HIP and HIP+HT condition are shown in Fig. 12, wherein the peaks corresponding to different phases have also been labelled [32], [33]. The γ" (BCC, Ni3Nb) phase diffraction spectra coincide with the γ (FCC, matrix) for 111γ||111γ", 200γ||200γ", and 220γ||220γ".…”

Section: Micro-hardness In As-built and Post-treated Conditionsmentioning

confidence: 94%

The Effect of Location and Post-treatment on the Microstructure of EBM-Built Alloy 718

Goel

Olsson

Ahlfors

et al. 2018

The Minerals, Metals &Amp; Materials Series

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Additive manufacturing (AM) of Ni-based superalloys such as Alloy 718 may obviate the need for difficult machining and welding operations associated with geometrically intricate parts, thus potentially expanding design possibilities and facilitating cost-effective manufacture of complex components. However, processing AM builds completely free from defects, which may impair mechanical properties such as fatigue and ductility, is challenging. Anisotropic properties, microstructural heterogeneities and local formation of undesired phases are additional concerns that have motivated post-treatment of AM builds. This work investigates the microstructural changes associated with post-treatment of Alloy 718 specimens produced by Electron Beam Melting (EBM) for as-built microstructures at 3 build heights: near base plate, in the middle of build and near the top of the build. Two different post-treatment conditions, hot isostatic pressing (HIP) alone and a combined HIP with solutionising and two-step aging were examined and compared to the results for the as-built condition. The influence of various posttreatments on minor phase distributions (, γ", carbides), overall porosity, longitudinal grain widths and Vickers microhardness was considered. The HIP treatment led to significant reduction in overall porosity and dissolution of  phase, which led to appreciable grain growth for both post-treatment conditions. The variation in hardness noted as a function of build height for the as-built specimens was eliminated after post-treatment. Overall, the hardness was found to decrease after HIP and increase after the full HIP, solutionising and aging treatment, which was attributed to dissolution of γ" during HIP and its re-precipitation in subsequent heat treatment steps.

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“…1b). In [16,18,19], such a microstructure was described as cellular with respect to equiaxed subgrains and dendritic with respect to columnar subgrains. Columnar subgrains, in turn, apparently consisted of equiaxed subgrains 0.5 -1 μm in size as was also observed in [7].…”

Section: Microstructure Of the Superalloy Obtained By Slmmentioning

confidence: 99%

Microstructure and mechanical properties of the Inconel 718 superalloy manufactured by selective laser melting

et al. 2019

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The work is devoted to the study of the microstructure and mechanical properties of the nickel base superalloy Inconel 718 manufactured by selective laser melting (SLM). Multiple cycles of heating and cooling during SLM led to the formation of a complex microheterogeneous microstructure. The microstructure of the superalloy manufactured by SLM consisted of elongated γ grains with a transversal size of 10 -100 μm and a longitudinal size of 50 -300 μm, which in its turn consisted of columnar and equiaxed subgrains. Stable and metastable precipitates of the δ-Ni 3 Nb and γ''-Ni 3 Nb phases, carbides and probably oxides, were detected along the subboundaries. The standard heat treatment of the superalloy manufactured by SLM resulted in a partial dissolution of the δ phase and the metastable γ'' phase during solid solution treatment and precipitation of the dispersed metastable γ'' phase during ageing. The microstructure characterization performed by electron backscatter diffraction technique (EBSD analysis) revealed that the size and elongated form of the γ grains was not changed after the heat treatment, the size of the subgrains slightly increased, the fraction of low-angle boundaries (subboundaries) decreased, and the fraction of high-angle grain boundaries increased. Tensile tests were carried out at T = 20 -700°C for the superalloy samples subjected to standard heat treatment. The tensile direction was parallel to the building direction. The tensile tests showed that the superalloy manufactured by SLM exceeded the requirements of the AMS 5662 certificate for the superalloy Inconel 718 in a hot forged condition subjected to standard heat treatment.

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Effect of different heat treatments on the microstructure and mechanical properties in selective laser melted INCONEL 718 alloy

Cited by 162 publications

References 13 publications

Nb rich precipitates in Inconel 718 produced by selective laser melting

Nb rich precipitates in Inconel 718 produced by selective laser melting

The Effect of Location and Post-treatment on the Microstructure of EBM-Built Alloy 718

Microstructure and mechanical properties of the Inconel 718 superalloy manufactured by selective laser melting

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