Site occupancy of chromium in the γ′-Ni<sub>3</sub>Al phase of nickel-based superalloys: a combined 3D atom probe and first-principles study

Chaudhari, Mrunalkumar; Singh, Abhishek; Gopal, Priya; Nag, S.; Viswanathan, G.B.; Tiley, J.; Banerjee, Rajarshi; Du, Jincheng

doi:10.1080/09500839.2012.690904

Cited by 25 publications

(16 citation statements)

References 26 publications

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“…Ti is only 19 at.% which deviates from the ideal Ni 3 (Al,Ti) stoichiometry. This implies that Al sublattices can be substituted by other solutes such as Cr and Ta [129,130].…”

Section: Matrix Phasementioning

confidence: 99%

Powder bed fusion additive manufacturing of Ni-based superalloys: a review of the main microstructural constituents and characterization techniques

et al. 2022

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Metal additive manufacturing (AM) has unlocked unique opportunities for making complex Ni-based superalloy parts with reduced material waste, development costs, and production lead times. Considering the available AM methods, powder bed fusion (PBF) processes, using either laser or electron beams as high energy sources, have the potential to print complex geometries with a high level of microstructural control. PBF is highly suited for the development of next generation components for the defense, aerospace, and automotive industries. A better understanding of the as-built microstructure evolution during PBF of Ni-based superalloys is important to both industry and academia because of its impacts on mechanical, corrosion, and other technological properties, and, because it determines post-processing heat treatment requirements. The primary focus of this review is to outline the individual phase formations and morphologies in Ni-based superalloys, and their correlation to PBF printing parameters. Given the hierarchal nature of the microstructures formed during PBF, detailed descriptions of the evolution of each microstructural constituent are required to enable microstructure control. Ni-based superalloys microstructures commonly include γ, γ′, γ′′, $$\delta$$ δ , TCP, carbides, nitrides, oxides, and borides, dependent on their composition. A thorough characterization of these phases remains challenging due to the multi-scale microstructural hierarchy alongside with experimental challenges related to imaging secondary phases that are often nanoscale and (semi)-coherent. Hence, a detailed discussion of advanced characterization techniques is the second focus of this review, to enable a more complete understanding of the microstructural evolution in Ni-based superalloys printed using PBF. This is with an expressed goal of directing the research community toward the tools necessary for a thorough investigation of the processing-microstructure-property relationships in PBF Ni-based superalloy parts to enable microstructural engineering.

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“…Ti is only 19 at.% which deviates from the ideal Ni 3 (Al,Ti) stoichiometry. This implies that Al sublattices can be substituted by other solutes such as Cr and Ta [129,130].…”

Section: Matrix Phasementioning

confidence: 99%

Powder bed fusion additive manufacturing of Ni-based superalloys: a review of the main microstructural constituents and characterization techniques

et al. 2022

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“…A number of studies have investigated the partitioning of transition metal elements (such as Cr, Co, W, and Ta) using both experimental and computational methods. Further, previous atom-probe tomography (APT), scanning electron microscopy (SEM), and atom location by channeling enhanced microanalysis (ALCHEMI) technique have concluded that Cr occupies the Al sub lattice in the γ' phase [10][11][12]. Chowdry et al, [12] studied the site occupancy behavior of Cr in γ'-Ni 3 Al using ab initio Density Functional Theory (DFT) computational studies and 3D atom probe tomography (APT).…”

Section: Introductionmentioning

confidence: 99%

“…Further, previous atom-probe tomography (APT), scanning electron microscopy (SEM), and atom location by channeling enhanced microanalysis (ALCHEMI) technique have concluded that Cr occupies the Al sub lattice in the γ' phase [10][11][12]. Chowdry et al, [12] studied the site occupancy behavior of Cr in γ'-Ni 3 Al using ab initio Density Functional Theory (DFT) computational studies and 3D atom probe tomography (APT). Their results show that chromium atoms prefer to be close by on either nickel or aluminum sublattices or on a nickel-aluminum mixed lattice, suggesting a potential tendency of chromium segregation in the γ' phase.…”

Section: Introductionmentioning

confidence: 99%

Effect of B and Cr on elastic strength and crystal structure of Ni3Al alloys under high pressure

Raju¹,

Oni²,

Godwal³

et al. 2015

Journal of Alloys and Compounds

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Samples of Ni 3 Al, Ni 3 Al:B and Ni-Al-Cr super alloys were prepared by directional solidification method and their effect of alloying with ternary elements on the mechanical properties was investigated. In-situ x-ray diffraction studies were carried out on undoped Ni 3 Al, Ni 3 Al:B with boron 500ppm and Ni-Al-Cr with 7.5 at% of chromium super alloys at high pressure using diamond anvil cell. The results indicate that micro-alloying with B forms γ'phase (L1 2 structure), similar to the pure Ni 3 Al, while Ni-Al-Cr alloy consists of γ' precipitates in a matrix of γ-phase (Ni-FCC structure). The crystal structure of all three alloys was stable up to 20 GPa. Micro alloying with boron increases bulk modulus of Ni 3 Al by 8% whereas alloying with chromium has the opposite effect decreasing the modulus by 11% when compared to undoped alloy. Further, the elastic modulus and hardness of Ni 3 Al, Ni 3 Al:B and Ni-Al-Cr alloys were determined using the nano-indentation technique, in combination with compressibility data which enabled the estimation of shear modulus and Poisson's ratio of these alloys.

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“…Modeling of peak intensities for different phase compositions provides a method of determining the most likely site occupancies. However, within γ', the elements change occupancy between Ni and Al sites depending on their neighbors [18] especially Co, which is sensitive to where the other elements are residing [20,21].…”

Section: Introductionmentioning

confidence: 99%

“…Chemical segregation between γ and γ' has been successfully studied and reported for a number of nickel base superalloys using computational approaches involving energy potentials, and alloying element segregation to either Al or Ni sites with γ' has been modeled for ternary alloy systems [18,19,20,21,22]. However, for alloy systems with more than a few different alloying elements, it becomes computationally difficult to determine energies for accurate site occupancy estimations, and experimentally difficult to apply transmission electron diffraction and Rietveld refinement using either neutron and/or x-ray diffraction techniques.…”

Section: Introductionmentioning

confidence: 99%

Determination of Gamma-Prime Site Occupancies in Nickel Superalloys Using Atom Probe Tomography and X-Ray Diffraction (Preprint)

Tiley¹,

Senkov²,

Viswanathan³

et al. 2012

Self Cite

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information SPONSORING/MONITORING AGENCY REPORT NUMBER(S)AFRL-RX-WP-TP-2012-0390 DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited. Preprint to be submitted to Metallurgical and Materials Transactions. SUPPLEMENTARY NOTESThe U.S. Government is joint author of this work and has the right to use, modify, reproduce, release, perform, display, or disclose the work. PA Case Number and clearance date: 88ABW-2012-2970, 21 May 2012. This document contains color. ABSTRACTRene88 samples were investigated using atom probe tomography and x-ray diffraction using a monochromated synchrotron beam with different energy values to determine the preferred site occupancy of various alloying elements within the ordered γ' precipitates. Samples were solutionized and cooled at 24 degree C/min with subsequent aging at 760 degrees C. The synchrotron-based x-ray diffraction results indicate that niobium prefers to reside on the aluminum sublattice site of the γ' phase. Additionally, the experimental results also indicate that chromium prefers the nickel sublattice sites while cobalt is likely to occupy both the aluminum and nickel sublattice sites. The x-ray results on the chromium occupancy disagree with atom probe results from the same alloy that indicate that chromium prefers the aluminum sublattice sites. Modeling studies indicate cobalt has no strong site preference. SUBJECT TERMS AbstractRene88 samples were investigated using atom probe tomography and x-ray diffraction using a monochromated synchrotron beam with different energy values to determine the preferred site occupancy of various alloying elements within the ordered γ' precipitates. Samples were solutionized and cooled at 24 degree C/min with subsequent aging at 760 degrees C. The synchrotron-based x-ray diffraction results indicate that niobium prefers to reside on the aluminum sublattice site of the γ' phase. Additionally, the experimental results also indicate that chromium prefers the nickel sublattice sites while cobalt is likely to occupy both the aluminum and nickel sublattice sites. The x-ray results on the chromium occupancy disagree with atom probe results from the same alloy that indicate that chromium prefers the aluminum sublattice sites. Modeling studies indicate cobalt has no strong site preference.

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Site occupancy of chromium in the γ′-Ni₃Al phase of nickel-based superalloys: a combined 3D atom probe and first-principles study

Cited by 25 publications

References 26 publications

Powder bed fusion additive manufacturing of Ni-based superalloys: a review of the main microstructural constituents and characterization techniques

Powder bed fusion additive manufacturing of Ni-based superalloys: a review of the main microstructural constituents and characterization techniques

Effect of B and Cr on elastic strength and crystal structure of Ni3Al alloys under high pressure

Determination of Gamma-Prime Site Occupancies in Nickel Superalloys Using Atom Probe Tomography and X-Ray Diffraction (Preprint)

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Site occupancy of chromium in the γ′-Ni3Al phase of nickel-based superalloys: a combined 3D atom probe and first-principles study

Cited by 25 publications

References 26 publications

Powder bed fusion additive manufacturing of Ni-based superalloys: a review of the main microstructural constituents and characterization techniques

Powder bed fusion additive manufacturing of Ni-based superalloys: a review of the main microstructural constituents and characterization techniques

Effect of B and Cr on elastic strength and crystal structure of Ni3Al alloys under high pressure

Determination of Gamma-Prime Site Occupancies in Nickel Superalloys Using Atom Probe Tomography and X-Ray Diffraction (Preprint)

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Site occupancy of chromium in the γ′-Ni₃Al phase of nickel-based superalloys: a combined 3D atom probe and first-principles study