The dependence of oxidation resistance on gamma prime intermetallic size for superalloy IN738LC

Mallikarjuna, H.T.; Caley, W. F.; Richards, N.L.

doi:10.1016/j.corsci.2018.12.002

Cited by 21 publications

(6 citation statements)

References 31 publications

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“…Heat‐treated conventional wrought and cast IN738LC alloys were reported to generally consist of a γ matrix, γ′ precipitates, carbides, and borides. [ 4,36 ] As a result, γ′ is understood to precipitate in FH and DA alloys by artificial aging (840 °C/24 h) regardless of the solid‐solution heat treatment.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…[1,2] Moreover, this superalloy offers excellent corrosion/ oxidation resistance at high temperature and in SO x and CO x atmospheres, it is used to be applied as parts exposed to high temperatures and corrosive environments such as turbine blades and vanes in aerospace and spacecraft, power plants industries. [3][4][5] Additive manufacturing (AM) has the following advantages: parts with complex shapes can be obtained, parts can be geometrically optimized, lightweight parts can be manufactured (lattice materials, foam, thin-wall structure, etc. ), simplified process, low material loss, and difficultto-process/poor machinable materials can be fabricated.…”

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Influence of Post‐Heat Treatments on the Microstructure, Mechanical Responses of IN738LC Superalloy Manufactured via Laser Powder Bed Fusion

2022

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IN738LC is a precipitation-hardening Ni-Cr-Ti-Al-based superalloy that exhibits excellent mechanical properties at room and high temperatures because of the formation of γ 0 -Ni 3 (Al, Ti) precipitates. [1,2] Moreover, this superalloy offers excellent corrosion/ oxidation resistance at high temperature and in SO x and CO x atmospheres, it is used to be applied as parts exposed to high temperatures and corrosive environments such as turbine blades and vanes in aerospace and spacecraft, power plants industries. [3][4][5] Additive manufacturing (AM) has the following advantages: parts with complex shapes can be obtained, parts can be geometrically optimized, lightweight parts can be manufactured (lattice materials, foam, thin-wall structure, etc.), simplified process, low material loss, and difficultto-process/poor machinable materials can be fabricated. [6][7][8] Accordingly, manufacturing Ni-based superalloy parts using AM has attracted widespread interest, and many studies on efficient manufacturing are currently actively continuing. [9][10][11][12] However, most studies of the use of Ni-based superalloys for AM focused on the IN625 [13][14][15][16] and IN718 [17][18][19][20][21][22][23] alloys, whereas little is reported about γ 0 -Ni 3 (Al, Ti) precipitate hardening Ni-based superalloys, which exhibit excellent mechanical properties.Manufacturing of IN738LC using laser powder bed fusion (LPBF), [24][25][26][27][28][29][30] electron beam powder bed fusion (EBPBF), [31,32] or direct energy deposition (DED) [33][34][35] processes has recently been attempted. However, it is difficult to manufacture a material without defects (i.e., cracks and pores) if the Al þ Ti content added to form γ 0 -Ni 3 (Al, Ti) is over 6 wt% because the material may give rise to liquation cracking, hot cracking, and weld cracking. [36][37][38] The high Al þ Ti content of IN738LC (6.2À7.2 wt%) makes it difficult to weld, and this motivated researchers to study the crack formation mechanism and crack control of IN738LC manufactured with AM. [27,28,33,37] Furthermore, an increasing need has arisen to investigate the microstructure control and the improvement in the mechanical properties of AM IN738LC by applying different post-heat treatments.Ni-based superalloys (mainly IN625 and IN718) fabricated by AM require multi-stage post-heat treatments such as stress relieving, hot-isostatic pressing, solid-solution strengthening, and artificial aging. [26,29,[39][40][41][42][43][44][45] Likewise, IN738LC could be expected to require similar post-heat treatments. Xu et al. [30] suggested that it was possible to control the mechanical properties of a Ni-based superalloy using the variation of γ 0 fraction and size with the hot isostatic pressing (HIP) temperature change. However, previous studies were carried out at high temperatures with complex heat treatment consisting of three or more steps and thus could affect the dimensional stability of the part. In contrast, it is known to be possible to control the mechanical properties of an AM Ni-based su...

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Influence of Post‐Heat Treatments on the Microstructure, Mechanical Responses of IN738LC Superalloy Manufactured via Laser Powder Bed Fusion

2022

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“…이와 같이 Al, Cr 성분인 ① 표면 산화층에 인접한 지 역은 ② γ' 석출상 고갈층을 형성한다 [12,13]. 이것은 γ' [10,13,14]. 그리고 ④ 표 면 재결정은 시험편 가공의 표면 잔류응력 또는 일방향 응 고 잔류 응력에 기인하는 구동력에 의해 발생되는 것으로 보고 된다 [15,16] 감사의 글…”

Section: 대한금속 • 재료학회지 제61권 제12호 (2023년 12월)unclassified

Effect of High Temperature Oxidation on Surface Pit and Recrystallization of Directionally Solidified CM247LC Superalloy in Creep Gauge

Choe,

Choi,

Han

et al. 2023

Korean J. Met. Mater.

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This study analyzed a recrystallization phenomenon that occurred simultaneously with hightemperature oxidation on the surface of a directionally solidified CM247LC creep specimen, using optical and scanning electron microscopy. After heat treatment, the surface of the specimen subjected to the creep test at 982oC was oxidized by exposure to high temperature and underwent microstructural changes due to high temperature stress. The outermost layer of the oxidized surface pits was found to consist of an oxide of the Cr/Co component, and the lower layer contained an oxide of the Al component. The area adjacent to the surface oxide layer is a precipitated free zone (PFZ) depleted of the y’ precipitated phase. The PFZ is caused by the diffusion of the Al component from this area to the surface oxide layer, resulting in the depletion of y'-Ni3Al as the main Al component. The area adjacent to the PFZ is a y' coarsening layer, which is the result of increasing y' phase fraction and coarsening as the Cr/Co component of this region diffuses into the PFZ of the y phase composition. This y' coarsening and y' rafting occurs in the direction perpendicular to the creep stress. In the EBSD analysis, the PFZ and y' coarsened layer were observed to be recrystallized regions, with the recrystallization composed of a single grain including the PFZ and y' coarsened layer. It is presumed that this recrystallization is caused by the residual stress of one-way solidification or the residual stress of the specimen surface processing. Accordingly, high-temperature oxidation in DS CM247LC creep gauge caused surface pits associated with recrystallization.

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“…More commonly, particles completely surrounded by other phases are evaluated by measuring their area [17] or assuming a certain geometric shape and calculating e.g. the diameter of a circle, or the edge length of a cube with equivalent area [17][18][19][20][21][22][23], as indicated in Fig. 1b.…”

Section: Introductionmentioning

confidence: 99%

3D Minimum Channel Width Distribution in a Ni-Base Superalloy

Müller

Böttger

Schleifer

et al. 2023

Integr Mater Manuf Innov

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The strength of a Ni-base superalloy depends strongly on its microstructure consisting of cuboidal $${\gamma }^{^{\prime}}$$ γ ′ precipitates surrounded by narrow channels of $$\gamma $$ γ matrix. According to the theory of Orowan, a moving dislocation has to crimp through the minimal inter-precipitate spacing to admit the plastic deformation. We present a novel approach to evaluate the matrix channel width distribution of a matrix/$${\gamma }^{^{\prime}}$$ γ ′ microstructure in binary representation. Our method relies on precise determination of the matrix/precipitate interfaces and requires no additional user input. For each matrix channel between two neighboring precipitates, we identify the minimal interface to interface distance vector with its length being the channel width. The performance of this method is demonstrated on the example of the commercial alloy CSMX-4. We show that, in contrast to conventional line sectioning approaches, the approach consistently handles experimental 2D micrographs and 3D phase-field simulation data. The identified distance vectors correlate to the underlying crystal symmetry independent of the image orientation. The obtained channel width distributions compare well between the 2D and 3D data. This is in terms of similar median and $$\sigma $$ σ of a log-normal distribution. The presented method overcomes limitations of the conventional line slicing approaches and provides a versatile tool for automated microstructure characterization.

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The dependence of oxidation resistance on gamma prime intermetallic size for superalloy IN738LC

Cited by 21 publications

References 31 publications

Influence of Post‐Heat Treatments on the Microstructure, Mechanical Responses of IN738LC Superalloy Manufactured via Laser Powder Bed Fusion

Influence of Post‐Heat Treatments on the Microstructure, Mechanical Responses of IN738LC Superalloy Manufactured via Laser Powder Bed Fusion

Effect of High Temperature Oxidation on Surface Pit and Recrystallization of Directionally Solidified CM247LC Superalloy in Creep Gauge

3D Minimum Channel Width Distribution in a Ni-Base Superalloy

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