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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 authors examined the statistics of liquid-to-crystal nucleation using a new generation automated lag-time apparatus denoted ALTA 4, and extracted the functional form which characterizes the average lag time, 〈τ〉, as a function of the degree of supercooling ΔT below the equilibrium freezing temperature, Tf.
Abstract: The statistics of liquid-to-crystal nucleation are examined using a new generation automated lag-time apparatus denoted ALTA 4. Two modes of operation are described and implemented. A single 200 μl sample of distilled water is cooled repeatedly at a constant rate, α, until the sample freezes. This cycle is repeated many hundreds of times, to generate the reliable and reproducible statistics for nucleation. From a single experiment, under a single testable approximation, we extract the functional form which characterizes the average lag-time, 〈τ〉, as a function of the degree of supercooling ΔT below the equilibrium freezing temperature, Tf. These data and the analysis yield, from a single experiment, a profile for the average lag-time, 〈τ〉, as a function of change in temperature, ΔT. Identical results are obtained over more than an order of magnitude of cooling rates α, from 0.6 to 7.5 K min−1 (0.01–0.125 K s−1).
46 citations
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TL;DR: In this paper, an analytical O-line method was developed to study the variation in the habit plane and its structure in a systematic manner, which has an advantage that the orientation relationship is the output from the calculation, while in many other models interpreting precipitation crystallography the OR is either an input or is constrained by a prerequisite condition.
Abstract: Precipitations that exhibit irrational transformation crystallography can often be explained in terms of the O-lines in the habit plane. The present work developed an analytical O-line method, which is more useful than the numerical O-line method to study the variation in the habit plane and its structure in a systematic manner. This method has an advantage that the orientation relationship (OR) is the output from the calculation, while in many other models interpreting precipitation crystallography the OR is either an input or is constrained by a prerequisite condition. This paper described the derivation of this method and its application to the study of the precipitation crystallography in fcc-bcc systems. Examples were given for three alloy systems, namely Cu-0.33 wt% Cr and Ni-45 wt% Cr alloys and a duplex-phase alpha-gamma stainless steel. The solutions include the OR between the precipitates and their matrix, the habit plane, the invariant line and the dislocation structure in the habit plane. The calculated results are in good agreement with the experimental observations reported in the literatures. Furthermore, the variation in the optimum O-line features with the lattice parameter ratio has also been studied systematically, providing some guidelines for estimating and understanding possible transformation crystallography from different fcc-bcc systems.
46 citations
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TL;DR: In this paper, the authors quantitatively investigated the Cu precipitation kinetics during martensite tempering of an Fe 0.44C-0.60Mn−0.53Cu (wt.%) steel by using electrical resistivity, smallangle neutron scattering (SANS), dilatometry, and thermodynamic calculations.
46 citations
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TL;DR: In this paper, a hypomonotectic alloy of Cu-5wt%Pb has been manufactured by melt spinning and the resulting microstructure examined by transmission electron microscopy.
Abstract: A hypomonotectic alloy of Cu-5wt%Pb has been manufactured by melt spinning and the resulting microstructure examined by transmission electron microscopy. As-melt spun hypomonotectic Cu-5wt%Pb consists of a homogeneous distribution of faceted 20–100 nm diameter Pb particles embedded in a matrix of Cu, formed during the monotectic solidification reaction. The Pb particles show a cube-cube orientation relationship with the surrounding Cu matrix and a truncated octahedral shape bounded by {111} and {100} facets. The kinetics of Pb particle solidification have been examined by heating and cooling experiments in a differential scanning calorimeter over a range of heating and cooling rates. Pb particle solidification is nucleated catalytically by the surrounding Cu matrix, with an undercooling of 0.5 K and a contact angle of 4°. Analysis of the nucleation kinetics of Pb particle solidification seems to indicate a breakdown of the classical spherical cap model of heterogeneous nucleation.
46 citations
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TL;DR: In this paper, the effects of the latent heat release on the kinetics of the olivine-spinel phase transition were investigated and the role of the thermo-kinetic coupling process was clarified.
46 citations