Crystallographic and lattice point correlations of a new hcp-to-fco martensitic transformation observed in the Ni–Hf system

Li, J.H.; Guo, Haibo; Liu, B.X.

doi:10.1016/j.actamat.2004.10.025

Cited by 6 publications

(3 citation statements)

References 16 publications

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“…36 Second, for the Ni-Hf system, there appear three critical points in the calculated MCI over the entire composition range, i.e., 16 atom % of Ni and 25 atom % of Ni, for the hcp Hfbased solid solution and 20 atom % of Hf for the fcc Ni-based solid solution, respectively, which coincidently match well with three specific compositions found previously for the Ni-Hf system, corresponding to a composition for forming a metastable face-centered orthorhombic (fco) phase and another two compositions defining the glass-forming range, respectively. 37,38 It is obvious that when the solute concentrations are less than the critical points, the MCI of the Ni-Hf system is very small, and that when the alloy compositions fall into the range of 16-80 atom % of Ni, the Ni-Hf alloys prefer to be in an amorphous state, resulting in forming metallic glasses, as the negative MCI means there is a tendency of ordering. 39 It is therefore concluded that the composition range determined from the calculated MCI agrees well with that predicated previously as well as with the experiment observations, as the Ni-Hf metallic glasses have readily been produced by some nonequilibrium materials processing techniques within the predicted compositions range.…”

Section: The Ag-ru and Ag-co Systemsmentioning

confidence: 99%

Proposed Definition of Microchemical Inhomogeneity and Application To Characterize Some Selected Miscible/Immiscible Binary Metal Systems

Kong

Liu

2004

J. Phys. Chem. B

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A new parameter is proposed to quantify the microchemical inhomogeneity (MCI) for a general multicomponent system and is applied to characterize some selected binary metal systems, i.e., the Ag-Ru, Ag-Co, Ni-Ru, and Ni-Hf systems, through molecular dynamics simulations. For the equilibrium immiscible Ag-Ru, Ag-Co, and Ni-Ru systems, ab initio calculations are performed to acquire some physical properties for fitting the respective n-body potentials. On the basis of the derived potentials, simulations reveal that in the highly immiscible Ag-Ru system, when the solute concentration is less than one of the critical values, i.e., either 6 atom % of Ru or 10 atom % of Ag, in the Ag-based and Ru-based solid solutions, respectively, the MCI is a small positive number and that when the solute concentration exceeds the critical values, i.e., falls in a composition range of 6-90 atom % of Ag, the MCI rises sharply to a large positive value ranging from 0.8 to 0.95, suggesting an incomplete-phase-separation tendency, which may result in forming a nanometer/ subnanometer scaled structure. Similar simulations reveal that for the medium immiscible Ag-Co system, the MCI is about +0.7 within a composition range of 10-85 atom % of Ag and that for the Ni-Ru system, characterized by a nearly zero heat of formation, the MCI is nearly zero over the entire composition range, suggesting a possible metastable isomorphous phase diagram for the system, in which amorphous alloy, namely metallic glass, is hardly formed. In the contrast, for the miscible Ni-Hf system featuring a large negative heat of formation, the MCI is negative and is about -0.17 within a composition range of 25-80 atom % Ni, in which a crystalline solid solution prefers to turn into an amorphous state, corresponding almost exactly to the glass-forming range known from experiments as well as from theoretical prediction.

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Section: The Ag-ru and Ag-co Systemsmentioning

confidence: 99%

Proposed Definition of Microchemical Inhomogeneity and Application To Characterize Some Selected Miscible/Immiscible Binary Metal Systems

Kong

Liu

2004

J. Phys. Chem. B

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“…Compared with experimental exploration as well as ab initio calculations, MD simulation has been frequently used to investigate phase transition, 13,[15][16][17][18] especially the martensitic transformation in metallic systems. [19][20][21] Considering their advantages in modelling the detailed mechanism of phase transition, MD simulations were conducted in the present research to investigate the martensitic transformation of Ti 100Àx Nb x alloys (x = 5, 10. .…”

Section: Introductionmentioning

confidence: 99%

The atomistic mechanism of hcp-to-bcc martensitic transformation in the Ti–Nb system revealed by molecular dynamics simulations

Liu

2015

Phys. Chem. Chem. Phys.

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Applying the constructed Ti-Nb potentials, molecular dynamics simulations were conducted to investigate the martensitic transformation of Ti100-xNbx alloys (x = 5, 10…25) from the α' phase (hcp) to the β phase (bcc). It is found that the transformation involved four phases, i.e. α', α'', fco (face-centered orthorhombic), and β phases. The structures of the obtained phases exhibit consistency with experimental data, verifying the validity of atomic simulations. The simulations not only revealed the processes of atomic displacements during the transformation, but also elucidated the underlying mechanism of the martensitic transformation at the atomic level. The martensitic transformation incorporates three types of coinstantaneous deformations i.e. slide, shear as well as extension, and the subsequent lattice constant relaxation. Furthermore, according to the proposed mechanism, the crystallographic correlation between the initial α' phase and the final β phase has been deduced. The simulation results provide a clear landscape on the martensitic transformation mechanism, facilitating our comprehensive understanding on the phase transition in the Ti-Nb system.

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“…Jin et al [6] had ever observed the hcp-to-fcc structural phase transition under IBM in the pure Hf film with the individual thickness of 400Å and discussed this structural phase transition based on the semiempirical Miedema's model and Li. et al [7] executed the MD simulation using a proven realistic n-body Hf-Ni potential to find the hcp-to-fco martensitic transformation in the Hf-Ni system. It seemed that the structural phase transitions in such a system were commonly inclined to happen and therefore, in the present work, we dedicated to investigate such a phenomenon of pure Hf films with different thicknesses and that of the Hf-Ni system with a sandwich structure with the aid of ab initio calculation and IBM.…”

Section: Introductionmentioning

confidence: 99%

Structural phase transition in the Hf–Ni system studied by ab initio calculation and ion beam mixing

Yan

Guo

Liu

2007

Journal of Alloys and Compounds

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Crystallographic and lattice point correlations of a new hcp-to-fco martensitic transformation observed in the Ni–Hf system

Cited by 6 publications

References 16 publications

Proposed Definition of Microchemical Inhomogeneity and Application To Characterize Some Selected Miscible/Immiscible Binary Metal Systems

Proposed Definition of Microchemical Inhomogeneity and Application To Characterize Some Selected Miscible/Immiscible Binary Metal Systems

The atomistic mechanism of hcp-to-bcc martensitic transformation in the Ti–Nb system revealed by molecular dynamics simulations

Structural phase transition in the Hf–Ni system studied by ab initio calculation and ion beam mixing

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