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The theory of transformations in metals and alloys
01 Jan 1965-
TL;DR: In this paper, the authors present a general introduction to the theory of transformation kinetics of real metals, including the formation and evolution of martensitic transformations, as well as a theory of dislocations.
Abstract: Part I General introduction. Formal geometry of crystal lattices. The theory of reaction rates. The thermodynamics of irreversable processes. The structure of real metals. Solids solutions. The theory of dislocations. Polycrystalline aggregates. Diffusion in the solid state. The classical theory of nucleation. Theory of thermally activated growth. Formal theory of transformation kinetics. Part II Growth from the vapour phase. Solidification and melting. Polymorphic Changes. Precipitation from supersaturated solid solution. Eutectoidal transformations. Order-disorder transformations. Recovery recrystalisation and grain growth. Deformation twinning. Characteristics of martensic transformations. Crystallography of martensitic transformations. Kinetics of martensitic transformations. Rapid solidification. Bainite steels. Shape memory alloys.
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TL;DR: In this paper, the effects of kinetics on the non-equilibrium aspects of the olivine to spinel transition in a descending slab have been studied numerically, and a one-dimensional model consisting of the kinetic equations and the heat-diffusion equation with latent-heat release has been constructed.
Abstract: The effects of kinetics on the non-equilibrium aspects of the olivine to spinel transition in a descending slab have been studied numerically. A one-dimensional model consisting of the kinetic equations and the heat-diffusion equation with latent-heat release has been constructed. Numerical results show that the position and sharpness of the kinetic phase boundary is determined by the surface tension and the activation volume. For slow slab velocities, less than 6 cm/yr, near equilibrium conditions are found. Finger-like structures emanating from the phase boundaries are obtained in this regime. These phase boundary prolusions may cause earthquakes. For slab velocities of around 10 cm/yr the metastable olivine region may be pushed down to a depth of about 600 km, with a sharp phase boundary. A direct transition from olivine to perovskite may be feasible.
40 citations
TL;DR: The kinetic behavior of quasicrystalline phase formation in amorphous Zr65Al7.5Cu12.5Ni10Ag5 alloys has been studied by using differential scanning calorimetry (DSC), x-ray diffractometry, and transmission electron microscopy as discussed by the authors.
Abstract: The kinetic behavior of quasicrystalline phase formation in amorphous Zr65Al7.5Cu12.5Ni10Ag5 alloys has been studied by using differential scanning calorimetry (DSC), x-ray diffractometry, and transmission electron microscopy. DSC trace obtained during continuous heating from 473 to 873 K shows two distinct exotherms with peak temperatures of 727 and 776 K. The first and second exothermic reactions, respectively, correspond to the formation of quasicrystalline phase from the amorphous matrix and the formation of tetragonal CuZr2 and hexagonal Zr6NiAl2 phases from the previously formed quasicrystalline phase. Partial replacement of Cu by Ag enhanced the formation of quasicrystalline phase from the amorphous structure. Johnson–Mehl–Avrami analysis of isothermal transformation data suggests that the formation of quasicrystalline phase is not entirely polymorphic in nature and may involve partitioning of solute at a later stage.
40 citations
01 Jan 1993
TL;DR: In this article, the authors reviewed the recent studies on the nucleation and kinetics of propagating phase boundaries in an elastic bar and related them to various admissibility criteria.
Abstract: This paper reviews our recent studies on the nucleation and kinetics of propagating phase boundaries in an elastic bar and relates them to various admissibility criteria. First, we discuss how the field equations and jump conditions of the quasi-static theory of such a bar must be supplemented with additional constitutive information pertaining to the initiation and evolution of phase boundaries. The kinetic relation relates the driving traction f at a phase boundary to the phase boundary velocity ṡ; thus f = φ (ṡ), where φ is a materially-determined function. The nucleation criterion specifies a critical value of f at an incipient phase boundary. We then incorporate inertial effects, and we find in the context of the Riemann problem that, as long as phase boundary velocities are subsonic, the theory again needs — and has room for — a nucleation criterion and a kinetic relation. Finally, we describe the sense in which each of three widely studied admissibility criteria for phase boundaries is equivalent to a specific kinetic relation of the form f = φ (ṡ) for a particular choice of φ A kinetic relation based on thermal activation theory is also discussed.
40 citations
TL;DR: The activation energy for nickel-induced lateral crystallization of amorphous silicon heated in an inert atmosphere was investigated in this paper, and was found to be 1.75 eV for rapid thermal annealing and 1.86 eV (1.86
Abstract: The activation energy for nickel-induced lateral crystallization of amorphous silicon heated in an inert atmosphere was investigated, and was found to be 1.75 eV for rapid thermal annealing and 1.86 eV for furnace annealing. Polycrystalline silicon thin-film transistors fabricated in furnace recrystallized and rapid thermal recrystallized material had similar device characteristics, even though the crystallization velocity differed by a factor of 3.
40 citations
TL;DR: In this article, the details of the martensite reaction have been investigated by thin foil electron microscopy techniques in high purity Ti-Cr binary alloys containing 2.4-5.9 at.
40 citations