Showing papers in "Acta Metallurgica in 1984"

TL;DR: In this article, a set of elastic-plastic constitutive relations that account for the nucleation and growth of micro-voids is used to model the failure of a round tensile test specimen.

TL;DR: In this article, a phenomenological treatment of plastic deformation is proposed which makes it possible to describe in a unified way the plastic behavior of a material both under dynamic loading and in creep.

TL;DR: In this paper, a Monte Carlo procedure is applied to the study of grain growth in two dimensions, where the initial distribution of orientations is chosen at random and the system evolves so as to reduce the number of nearest neighbor pairs of unlike crystallographic orientation.

TL;DR: In this paper, the role of the strain and strain rate gradients in raising the apparent torsion peak strain ep above the ep values obtained from homogeneous tension or compression testing is clarified.

TL;DR: In this paper, a functional form for the activation enthalpy of cross slip of a 12 [101] (111) dislocation has been derived using the results of recent atomistic studies of screw dislocations in L12 structures.

TL;DR: In this article, the validity of using an equivalence criterion to describe the plastic properties of polycrystals at large strains is addressed from the point of view of the microscopic properties of the constituent grains.

TL;DR: In this article, the authors analyzed the microstructures produced by the grain growth simulation technique described in the previous paper and found that the grain size distribution function is time invariant when the grain sizes, R, is scaled by the mean grain size, R, and is shown to fit the experimental data better than either the log-normal function or the grain distribution function suggested by Hillert.

TL;DR: In this paper, a new kinetic model for anisothermal metallurgical transformations, valid for diffusion controlled as well as martensitic transformations, is proposed, which is first described in the case of two phases and a unique transformation, then extended to n phases and several (possibly simultaneous and unsymmetrical) transformations.

TL;DR: In this paper, a scanning laser beam is used to modify the surface properties of the near-surface of a surface. The beam subjects the near surface to a thermal cycle with an amplitude and shape which depends on the process variabl...

TL;DR: In this article, a new phenomenological description of grain growth based on the concept of the variation in mobility of individual grain boundaries allows three characteristic regimes of growth to be distinguished, and a new model for grain growth allied with surface diffusion mechanisms can explain in a consistent manner the experimentally observed grain structures.

TL;DR: In this paper, the authors evaluated the site preference of ternary additions in Ni3Ga, Ni3Si, Ni 3Ge and Ni3Al, together with the available information on ternaries phase diagrams, and showed that the extent of solubility lobe can be explained on the two dimensional map, proposed by Alonso and Simozar.

TL;DR: In this article, the mechanical properties of three types of cellular solids (flexible, plastic and brittle) have been measured as a function of density; the results are compared with models for the stiffness, strength and densification; and constitutive laws are developed.

TL;DR: In this paper, the axial forces induced by polycrystalline samples of Al, Cu and α-Fe of commercial purity were tested in torsion over the temperature range 20 −400, 500 and 800°C, respectively.

TL;DR: This paper showed that although the flow stress is a linear function of pressure, the plastic dilatancy is not related by the normality flow rule and is in fact negligible by comparison.

TL;DR: In this article, a double-crystal diffractometer with self-compensation of wave-length dispersion and practically negligible instrumental line-broadening was used to investigate the Bragg reflections.

TL;DR: In this article, the role of surface forces on deformation and adherence of metal microcontacts is reviewed and the condition of existence of each mode as a function of the five parameters involved (Young's modulus, elastic limit, surface energy, radius of curvature and load).

TL;DR: In this paper, the results of the relaxed constraints (RC) theory and of the full constraints (FC) classical theory (Taylor/Bishop and Hill) were compared with those of experiments, and the RC results correspond far better to the experimental textures, which tend towards a unique end orientation.

TL;DR: In this paper, the multi-particle diffusion problem (MDP) is treated by an embedding technique, where growing and shrinking domains are represented by point sources or sinks, and a novel formulation is developed based on the concept of an interaction matrix, the elements of which are Ewald sums.

TL;DR: In this article, the authors used the multi-particle diffusion solution to determine the collective behavior of a system of dispersed second phase particles undergoing Ostwald ripening and found that the collective behaviour of the coarsening ensemble was highly dependent on the initial distribution.

TL;DR: In this article, the shape memory effect governed by the γ → e martensitic transformation has been studied in single crystals of several FeMn-Si alloys.

TL;DR: In this paper, a Monte Carlo computer simulation technique has been developed which models grain growth in the presence of a particle dispersion, allowing for the monitoring of an evolving microstructure as a function of time.

TL;DR: In this paper, the authors explore the recent discoveries by Williams of unusual phase diagram features for coherent phase equilibrium and explore a model that leads to a simple formulation involving only the minimization of a polynomial free energy function that includes an elastic energy term.

TL;DR: The crystal structure and morphology of hydride (deuteride) precipitates were investigated in this paper, where the deuteride was found to have a face-centered tetragonal structure (c/a = 1.09) with an ordered arrangement of hydrogen.

TL;DR: Theoretical models of fusion welding are developed and calibrated by using experimental data in this paper, where simple kinetic models for grain growth and particle dissolution are used to construct diagrams which described these processes in the heat-affected zone of a weld as a function of process variables (input energy, weld speed, preheat etc.).

TL;DR: In this article, the authors analyzed the time dependent sintering of a bi-modal powder compact, consisting of two regions which sinter at different rates, and obtained complete solutions for the internal stress and for the densification rate.

TL;DR: In this paper, the authors investigated the dependence of the microstructure on γ pl and its possible consequences and found that the decrease of critical stress required for the development of PSBs with increasing γpl is related to the corresponding variations in the matrix structure.

TL;DR: In this paper, the sources of the multiplicity of metastable structures of grain boundaries are discussed using a recently developed structural unit model of grain boundary structure and the results of computer calculations of symmetrical tilt boundaries are presented.

TL;DR: In this article, the critical resolved shear stress (CRSS) for (111) to (010) slip was found to depend on the test temperature and orientation of the samples, as other investigators have previously observed, but also on the sense of applied stress.

TL;DR: In this article, a geometrical model is used to show how the recovery of this damage by boundary migration, enhances the normal grain growth process, based on the postulate of Holm el al.

TL;DR: In this article, shape change transitions of elastically misfitting inclusions were predicted to occur when the inclusions are softer than the matrix, and the shape is dictated by minimizing interfacial energy without regard to the elastic contribution.