Size-dependent structural phase transition of face-centered-cubic metal nanowires

Xu, Ke

doi:10.1557/jmr.2007.0153

Cited by 4 publications

(3 citation statements)

References 48 publications

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“…Finally, surface stress can play a significant role in structural changes in nanowires. For instance, in the absence of surface reconstruction, fcc h100i Au and Pt nanowires spontaneously relax to the bct structure when the wire diameter is less than 2 nm [see Haftel and Gall (2006) and also Ma and Xu (2007)]. In a molecular-dynamics study of Fe and Mo, Kotrechko, Filatov, and Ovsjannikov (2006) concluded that bcc nanocrystals develop shear instability under uniaxial and hydrostatic tension.…”

Section: Nanostructuresmentioning

confidence: 99%

Lattice instabilities in metallic elements

et al. 2012

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Most metallic elements have a crystal structure that is either body-centered cubic (bcc), facecentered close packed, or hexagonal close packed. If the bcc lattice is the thermodynamically most stable structure, the close-packed structures usually are dynamically unstable, i.e., have elastic constants violating the Born stability conditions or, more generally, have phonons with imaginary frequencies. Conversely, the bcc lattice tends to be dynamically unstable if the equilibrium structure is close packed. This striking regularity essentially went unnoticed until ab initio total-energy calculations in the 1990s became accurate enough to model dynamical properties of solids in hypothetical lattice structures. After a review of stability criteria, thermodynamic functions in the vicinity of an instability, Bain paths, and how instabilities may arise or disappear when pressure, temperature, and/or chemical composition is varied are discussed. The role of dynamical instabilities in the ideal strength of solids and in metallurgical phase diagrams is then considered, and comments are made on amorphization, melting, and low-dimensional systems. The review concludes with extensive references to theoretical work on the stability properties of metallic elements.

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Section: Nanostructuresmentioning

confidence: 99%

Lattice instabilities in metallic elements

et al. 2012

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“…Structural transformations have also been investigated: pseudo-elasticity or shape memory showing a critical temperature in fcc metallic nanowires [18,[21][22][23], or the martensitic phase transformation induced by stress in NiAl [24]. Ma and Xu [25] employed molecular-dynamics simulation to investigate structural phase transitions in Au nanowires driven by surfacetension-induced intrinsic stress. Finally, transformations occurring in Fe nanowires have been studied and the effects of tensile strain on reorientation and phase change have been reported [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Computer simulation of strain-induced phase transformations in thin Fe films

Wang¹,

Urbassek²

2013

Modelling Simul. Mater. Sci. Eng.

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Using molecular-dynamics simulation and the Meyer–Entel potential, we study the response of thin Fe films (thickness ⩽10 nm) to tensile in-plane strain. The simulations are performed at a temperature slightly below the equilibrium phase transition temperature. For the four surface orientations studied, we typically find the following sequence of transformations in the strained films: (i) a bcc → hcp transition; (ii) the partial back transformation to the bcc phase; (iii) grain refinement: (iv) finally, intergranular fracture occurs. The bcc → hcp transformation follow the Burgers path in all cases. The role of twinning and dislocation formation is minor compared to that of phase transformation. Film thickness does not play a major role in the sequence of occurring film transformations. However, thinner films allow for a faster nucleation of the new phase. Nucleation starts at the surface; the role of homogeneous nucleation in the film interior is minor.

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“…In face-centered cubic (fcc) metals, pseudo-elasticity or shape-memory behavior [9,[13][14][15] as well as stress-induced phase transitions [16] have been discussed. Ma et al [17,18] report on surface-tension-induced structural phase transitions. For body-centered cubic (bcc) metals, Sandoval and Urbassek [19][20][21] studied both the temperature and stress induced phase transition in iron nanowires, and a rich variety of features-such as re-orientation and back-transformation to the original structure at high strain-have been reported.…”

Section: Introductionmentioning

confidence: 99%

Martensitic and austenitic phase transformations in Fe–C nanowires

Wang¹,

Sak-Saracino²,

Sandoval³

et al. 2014

Modelling Simul. Mater. Sci. Eng.

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Using molecular-dynamics simulation, we study the austenitic and martensitic phase transformation in Fe–C nanowires with C contents up to 1.2 at%. The transformation temperatures decrease with C content. The martensite temperature decreases with wire diameter towards the bulk value. During the transformation, the bcc and fcc phases obey the Kurdjumov–Sachs orientation relationship. For ultrathin wires (diameter D ⩽ 2.8 nm), we observe wire buckling as well as shape-memory effects. Under axial tensile stress the martensite transformation is partially suppressed, leading to strong plastic deformation. Under the highest loads, the austenite only partially back-transforms while the crystalline phases in the wire re-orient giving the multi-phase mixture a high tensile strength.

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Size-dependent structural phase transition of face-centered-cubic metal nanowires

Cited by 4 publications

References 48 publications

Lattice instabilities in metallic elements

Lattice instabilities in metallic elements

Computer simulation of strain-induced phase transformations in thin Fe films

Martensitic and austenitic phase transformations in Fe–C nanowires

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