Atomic ordering characteristics of Ni3Al intermetallics with substitutional ternary additions

Mekhrabov, Amdulla O.; Akdeniz, M. Vedat; Arer, M.M.

doi:10.1016/s1359-6454(96)00238-8

Cited by 32 publications

(21 citation statements)

References 14 publications

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“…The experimentally determined equilibrium composition of the γ'-precipitate phase of 75.24 Ni-16.48 Al-3.20 Cr-5.03 Ta at.% suggests that Al, Ta and Cr occupy the Al sites of the L1 2 -ordered Ni 3 Al-type γ'-precipitate phase of the Ni-Al-Cr-Ta alloy at 1073 K. Previous APT, atom probe field-ion microscope (APFIM) [30,32,33], x-ray analysis [34,35], and diffusion couple technique [31] experiments, as well as results of Monte Carlo simulations [36] and calculations employing first-principles [37][38][39][40], the cluster variation method [41][42][43][44], and other techniques [45,46], have shown that Ta occupies the Al sites in the ordered Ni 3 Al structure. These results contradict experimental results from ion channeling and nuclear reaction studies [47] and results based on short-range ordering parameters determined from pseudopotential approximations [48], which conclude that Ta occupies the Ni sites in the Ni 3 Al structure. Chromium has been found to occupy both the Ni or Al sites, depending on the composition of the alloy studied [34,36,37,39,43,48,49].…”

Section: Compositional Evolutioncontrasting

confidence: 83%

“…These results contradict experimental results from ion channeling and nuclear reaction studies [47] and results based on short-range ordering parameters determined from pseudopotential approximations [48], which conclude that Ta occupies the Ni sites in the Ni 3 Al structure. Chromium has been found to occupy both the Ni or Al sites, depending on the composition of the alloy studied [34,36,37,39,43,48,49].…”

Section: Compositional Evolutioncontrasting

confidence: 83%

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Effects of a Tantalum Addition on the Morphological and Compositional Evolution of a Model Ni-Al-Cr Superalloy

Booth-Morrison

Noebe

Seidman

et al. 2008

Superalloys 2008 (Eleventh International Symposium)

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The effects of a 2.0 at.% addition of Ta to a model Ni-Al-Cr superalloy aged at 1073 K are assessed using scanning electron microscopy and atom-probe tomography. The addition of Ta results in appreciable strengthening, and the morphology is found to evolve from a bimodal distribution of spheroidal precipitates, to cuboidal precipitates aligned along the elastically soft <001>-type directions. Tantalum is observed to partition preferentially to the γ'-precipitate phase and decreases the mobility of Ni in the γ-matrix sufficiently to cause an accumulation of Ni on the γ-matrix side of the γ'-precipitate/γ-matrix heterophase interface.

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Section: Compositional Evolutioncontrasting

confidence: 83%

Section: Compositional Evolutioncontrasting

confidence: 83%

Effects of a Tantalum Addition on the Morphological and Compositional Evolution of a Model Ni-Al-Cr Superalloy

Booth-Morrison

Noebe

Seidman

et al. 2008

Superalloys 2008 (Eleventh International Symposium)

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“…[27][28][29][30][31][32][33][34][35] The partial ordering energy of an A-B pair in ternary alloys can be defined as where F AB ðqÞ ¼ À…”

Section: Calculation Of Ordering Energiesmentioning

confidence: 99%

“…[30,31] In the present work, a similar approach is used to quantify the site selection characteristics of alloying elements in the c-TiAl. We employed the common canonical ensemble MC method with the Ising-type Hamiltonian being composed of ordering energies of pairs given as…”

Section: Simulation Proceduresmentioning

confidence: 99%

Site Selection and Pseudo-Clustering Behaviors of Alloying Elements in Aluminum-Lean γ-TiAl Intermetallics

Aykol

Mekhrabov

Akdeniz

2009

Metall Mater Trans A

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MURATAHAN AYKOL, AMDULLA O. MEKHRABOV, and M. VEDAT AKDENIZSite selection and pseudo-clustering behaviors of the various M alloying elements in Al-lean Ti 50 Al 50-X M X (X = 1, 2, 3, 4, and 5 at. pct) intermetallics have been investigated by means of the ordering energy-dependent and long-range-order forced fast Monte Carlo simulation method. The ordering energies have been calculated via pseudopotential approximation in the electronic theory of alloys up to the third coordination sphere (CS) taking the anisotropic nature of tetragonal L1 0 -type structure of c-TiAl into account. It was shown that the site occupation characteristics of the M alloying element atoms in c-TiAl intermetallics are governed by the relative magnitude of partial ordering energies between Ti-M and Al-M atomic pairs. However, the sign of partial ordering energies of these atomic pairs at the first CS becomes important in determining the clustering behavior and controls the dissolution modes of alloying element atoms in the c-TiAl matrix. The pseudo-clustering behavior of alloying elements reveals three dissolution modes, namely, random dissolution (mode I), planar clustering in two dimensions (mode II), and three-dimensional (3-D) clustering (mode III) of the M occupant atoms.

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“…Antisite defects are prevalent in an ordered Ni 3 Al intermetallic, which is responsible for engineering failures in practical applications. Ni 3 Al has attracted considerable attention from both experimental and theoretical points of view for its excellent oxidation resistance and exceptional high temperature yield stress [1][2][3][4][5]. A comprehensive knowledge of point defects is essential, because it is well known that the mechanical properties of Ni-Al alloys are closely related to the defect.…”

Section: Introductionmentioning

confidence: 99%

Microscopic phase field study of the antisite defect of Ni3Al in binary Ni-Al alloys

Zhang

Zheng

et al. 2010

Sci. China Phys. Mech. Astron.

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The temporal evolution feature of a microscopic phase field model is utilized to study the antisite defects of L1 2 -Ni 3 Al; this is quite different from other physicist' interests. There are mainly two points in brief. Firstly, antisite defects Ni Al and Al Ni , which are caused by the deviation from the stoichiometric Ni 3 Al, coexist in the Ni 3 Al phase. The surplus Ni atom in the Ni-rich side is prone to substitute Al thus producing the antisite defect Ni Al that maintains the stability of the L1 2 structure. In other case, the surplus Al atom in the Al-rich side is accommodated by a Ni sublattice consequently giving rise to antisite defect Al Ni . The calculated equilibrium occupancy probability of Ni Al is much higher than that of Al Ni . This point is generally in line with other theoretical and experimental works. Additionally, both Ni Al and Al Ni have a strong negative correlation to time step during the disorder-order transformation. Since the initial value of Ni Al and Al Ni on each site of the matrix is right at the concentration that we set, we can observe the decrease process of Ni Al and Al Ni from the initial disordered high anti-structure state to their respective equilibrium state, i.e. to the result of the ordering process further coarsening. antisite defect, L1 2 -Ni 3 Al, temporal evolution, microscopic phase field model PACS: 61.72.-, 61.50.Ah, 81.30.Mh

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Atomic ordering characteristics of Ni3Al intermetallics with substitutional ternary additions

Cited by 32 publications

References 14 publications

Effects of a Tantalum Addition on the Morphological and Compositional Evolution of a Model Ni-Al-Cr Superalloy

Effects of a Tantalum Addition on the Morphological and Compositional Evolution of a Model Ni-Al-Cr Superalloy

Site Selection and Pseudo-Clustering Behaviors of Alloying Elements in Aluminum-Lean γ-TiAl Intermetallics

Microscopic phase field study of the antisite defect of Ni3Al in binary Ni-Al alloys

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