First-principles investigation of electronic, mechanical and thermodynamic properties of L12 ordered Co3(M, W) (M = Al, Ge, Ga) phases

Xu, Weiwei; Han, Jiajia; Wang, Y.; Wang, C.P.; Liu, X.J.; Liu, Z.-K.

doi:10.1016/j.actamat.2013.05.032

Cited by 76 publications

(41 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The schematics detailing the indexing of coexisting Fig. 4a, c, and d establishes a three-phase coexistence of B2, DO 19 , and c1 in the cellular region. We note that in the diffraction pattern, there is no signature of L1 2 ordering.…”

Section: Resultsmentioning

confidence: 97%

“…The front consists of alternating layers of c solid solution and lamellae of DO 19 Co 3 (Mo, Nb) and B2 CoAl. Cellular precipitation originating from grain boundaries is well known [31,32].…”

Section: Resultsmentioning

confidence: 99%

“…Figure 3c shows a diffraction pattern taken along [011] matrix zone axis from a region that contains needle-shaped precipitates. The main reflections belong to fcc c-Co while the superlattice spots could be indexed as the DO 19 structure that corresponds to the Co 3 (Mo, Nb) needle precipitates. Along with these, one can also observe weak superlattice spots in between the transmitted beam and 200 type of matrix reflections.…”

Section: Resultsmentioning

confidence: 99%

“…Some reports state that Mo can replace up to 2 at.% W [21][22][23]. Further addition leads to the precipitation of needle-type Co 3 Mo precipitates with DO 19 structure that coexist with the L1 2 -ordered c 0 Co 3 (Al, W) precipitates in a fcc c-Co matrix [24,25]. The presence of these needle-type precipitates reduces the ductility and the alloy fractures in a brittle manner.…”

Section: Introductionmentioning

confidence: 95%

“…The morphologies and volume fractions of phases observed in the microstructures of these alloys are highly sensitive to alloying with elements like Ni, Ti, Mo, B, Cr, and Ta [11][12][13][14][15][16]. The thermodynamics and phase stability of the ordered c 0 structure have been studied using density functional theory (DFT) calculations by various groups [17][18][19][20]. These studies indicate that W is crucial for stabilizing the L1 2 structure of the c 0 phase giving rise to Co 3 (Al, W) stoichiometry.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Phase evolution and crystallography of precipitates during decomposition of new “tungsten-free” Co(Ni)–Mo–Al–Nb γ–γ′ superalloys at elevated temperatures

et al. 2016

View full text Add to dashboard Cite

This article reports the microstructural stability and consequent phase decomposition including the appearance of topologically close-packed (TCP) phases at high temperature of recently discovered tungsten-free c-c 0 alloys of base composition Co-10Al-5Mo-2Nb with or without the addition of Ni and Ti. On prolonged aging at 800°C of the Co-10Al-5Mo-2Nb alloy, needle-shaped DO 19 -ordered precipitates with stoichiometry of Co 3 (Mo, Nb) start appearing in the microstructure. In addition, growth of cellular domains from the grain boundaries featuring a three-phase composite lamellar structure could be observed. These phases are fcc c-Co with composition different from the original matrix, CoAl with B2 ordering and Co 3 (Mo, Nb) with DO 19 ordering. All the phases exhibit well-defined crystallographic orientation relationships. The decomposition of the alloys depends on the solvus temperature of the c 0 phase. The Nicontaining alloy exhibits no phase decomposition until 100 h of aging at 800°C without any significant effect on c 0 volume fraction (76 %). However, at 950°C, the alloy decomposes leading to the appearance of four different phases including TCP phases: a Cr 3 Si-type cubic phase, a hexagonal Laves phase, rhombohedral l phase, and solid solution of Co phase. The c-c 0 microstructure in the Co-10Al-5Mo-2Nb and Co-30Ni-10Al-5Mo-2Ta alloys is not stable at 800 and 950°C, respectively, on long-term aging. This shows that the measured solvus temperatures (i.e., 866 and 990°C) are metastable solvus temperatures. We also report that the Ti-containing alloy exhibits superior stability with no evidence of either TCP phase formation or any other decomposition of c 0 precipitates, even after aging at 950°C for 100 h.

show abstract

Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Phase evolution and crystallography of precipitates during decomposition of new “tungsten-free” Co(Ni)–Mo–Al–Nb γ–γ′ superalloys at elevated temperatures

et al. 2016

View full text Add to dashboard Cite

show abstract

New insight into the structural and physical properties of AlH ₃

Pan

2022

Intl J of Energy Research

View full text Add to dashboard Cite

Summary AlH3 hydride is a typical hydrogen storage material due to the high storage, low density and low temperature decomposition temperature, but the structural feature of AlH3 remains controversial. In addition, the optical properties of AlH3 are unclear. In this work, the first‐principles method is used to study the structural, optical and electronic properties of AlH3 hydride. Two possible AlH3 hydrides, viz. rhombohedral and cubic structures are considered. The stability of the rhombohedral AlH3 is demonstrated based on the analysis of phonon dispersion. Moreover, the band gap of rhombohedral and cubic AlH3 is 2.170 and 0.656 eV, respectively. Naturally, the semiconductor feature of AlH3 is related to the band separation of H‐s state and Al‐3p state. The dielectric functional diagram demonstrates the semiconductor properties of AlH3 hydride. Furthermore, it is found that the AlH3 shows the ultraviolet response.

show abstract

Elastic and thermodynamic properties of the Ti₂AlNb orthorhombic phase from first‐principles calculations

Jinchang

Wei

et al. 2017

Physica Status Solidi (b)

View full text Add to dashboard Cite

Ti2AlNb‐based alloy with a dominated orthorhombic phase is one of the most promising high‐temperature structural materials. In this work, the equilibrium volume, elastic, and thermodynamic properties of the ordered O phase with stoichiometric Ti2AlNb were predicted under different temperatures using first‐principles calculations based on density functional theory combined with quasi‐harmonic approximation (QHA). With the increase of temperature from 0 to 1300 K, the elastic properties decrease moderately and the bonding strength weakens slightly. The intrinsic properties of the Ti2AlNb O phase are ductile at all temperature considered. In order to explore the evolution mechanism of the temperature‐dependent elastic properties further, the density of state (DOS) has been analyzed. The stoichiometric Ti2AlNb O phase shows good high‐temperature mechanical and thermal stability, which is a kind of potential high‐temperature alloy applied in aeronautics industries.

show abstract

First-principles investigation of electronic, mechanical and thermodynamic properties of L12 ordered Co3(M, W) (M = Al, Ge, Ga) phases

Cited by 76 publications

References 65 publications

Phase evolution and crystallography of precipitates during decomposition of new “tungsten-free” Co(Ni)–Mo–Al–Nb γ–γ′ superalloys at elevated temperatures

Phase evolution and crystallography of precipitates during decomposition of new “tungsten-free” Co(Ni)–Mo–Al–Nb γ–γ′ superalloys at elevated temperatures

New insight into the structural and physical properties of AlH ₃

Elastic and thermodynamic properties of the Ti₂AlNb orthorhombic phase from first‐principles calculations

Contact Info

Product

Resources

About

First-principles investigation of electronic, mechanical and thermodynamic properties of L12 ordered Co3(M, W) (M = Al, Ge, Ga) phases

Cited by 76 publications

References 65 publications

Phase evolution and crystallography of precipitates during decomposition of new “tungsten-free” Co(Ni)–Mo–Al–Nb γ–γ′ superalloys at elevated temperatures

Phase evolution and crystallography of precipitates during decomposition of new “tungsten-free” Co(Ni)–Mo–Al–Nb γ–γ′ superalloys at elevated temperatures

New insight into the structural and physical properties of AlH 3

Elastic and thermodynamic properties of the Ti2AlNb orthorhombic phase from first‐principles calculations

Contact Info

Product

Resources

About

New insight into the structural and physical properties of AlH ₃

Elastic and thermodynamic properties of the Ti₂AlNb orthorhombic phase from first‐principles calculations