Search Results for zener-smith pinning

The misorientation of a boundary of a growing grain is defined not only by its crystallography but also by the crystallography of the grain into which it is growing. This article focuses on the Monte Carlo Potts model that is typically used to model grain growth, Zener-Smith pinning, abnormal grain growth, and recrystallization. It introduces the basics of the model, providing details of the dynamics, simulation variables, boundary energy, boundary mobility, pinning systems, and stored energy. The article explains how to incorporate experimental parameters and how to validate the model by comparing the observed behavior quantitatively with theory. The industrial applications of the model are also discussed. The article also provides a wide selection of the algorithms for implementing the Potts model, such as boundary-site models, n -fold way models, and parallel models, which are needed to simulate large-scale industrial applications.

This article is a comprehensive collection of terms related to metalworking operations that produce shapes from forging, extrusion, drawing, and rolling operations.

This article is a compilation of definitions of the terms related to sheet metal forming and fabrication.

Sintering is a thermal treatment process in which a powder or a porous material, already formed into the required shape, is converted into a useful article with the requisite microstructure. Sintering can be classified as solid-state, viscous, liquid-phase, and pressure-assisted (or pressure) sintering. This article provides information on the mechanisms and theoretical analysis of sintering and focuses on the types, mechanisms, process and microstructural variables, computer simulation, stages, and fundamentals of densification and grain growth of solid-state sintering and liquid-phase sintering. It describes the models for viscous sintering and the methods used in pressure-assisted sintering, namely, uniaxial hot pressing, hot isostatic pressing, sinter forging, and spark plasma sintering.

This article provides an overview of integrated weld modeling and presents strategic goals for the welding industry. It discusses the fundamentals of the underlying physics and the methodologies to solve the same. The article presents the pioneering work done to predict the heat-affected zone and weld metal microstructure in the early 1980s and 1990s. Applications of computational thermodynamics and kinetics tools to weld metal microstructure prediction for liquid-gas reactions and liquid-slag reactions that happen as a function of high-to-low temperature during fusion welding are discussed. The article also includes a brief discussion on weldability prediction, residual stress prediction, and distortion prediction. It concludes with information on the use of optimization methodologies.

Copper steels are precipitation-strengthened steels that are designed to have a unique combination of physical and mechanical properties. This article provides an overview of copper precipitate-strengthened steels and their applications, and discusses appropriate ASTM International standards. It describes the common phases and alloying elements present in copper precipitate-strengthened steels, and reviews the influences of alloying elements on processing, phase diagrams, microstructures, and mechanical properties. The article also discusses the thermomechanical process, solutionizing heat treatment, and isothermal aging in detail. It concludes with a review of the interrelationships between heat treatments, microstructures, and mechanical properties.

This article is a compilation of definition of the terms related to modeling for metals processing.

This article provides an overview of integrated weld modeling and discusses the fundamentals of the underlying physics and methodologies involved in process modeling. It presents approaches for microstructure modeling that help to predict phase fractions as well as grain size in the heat-affected zone and weld metal region as a function of alloy composition and thermal cycles. The article discusses the uses of computational thermodynamic and kinetic tools. It describes the concept of performance modeling, whose goal relates to the prediction of weldability, geometrical distortion, and/or locked-in residual stress as a function of material, restraint, process, and process parameters as well as service temperature. Finally, the article presents a case study, evaluating the use of X-65 steels using the E-WeldPredictor tool.

Grain boundaries are interfaces between crystallites of the same phase but different crystallographic orientation. They can be characterized as being low angle or high angle. This article discusses the measurements of grain-boundary energy with a brief summary of different schemes for measuring grain-boundary surface tension. The atomistic simulations of grain-boundary energy, measurement of grain-boundary migration and the techniques used to monitor grain-boundary migration are reviewed. Several considerations and effects influencing the computation of grain-boundary mobility are also discussed.

This article is a compilation of definition of the terms related to simulation of metals processing.

Solid-state transformations from invariant reactions are of three types: eutectoid, peritectoid, and monotectoid transformations. This article focuses on structures from eutectoid transformations with an emphasis on the classic iron-carbon system of steel. It illustrates the morphology of a pearlite nodule and the effect of various substitutional alloy elements on the eutectoid transformation temperature and effective carbon content, respectively. Peritectic and peritectoid phase equilibria are very common in several binary systems. The article reviews structures from peritectoid reactions and details the formation of peritectic structures that can occur by at least three mechanisms: peritectic reaction, peritectic transformation, and direct precipitation of beta from the melt.

This article reviews the basic mechanisms of elevated-temperature behavior and associated design considerations, with an emphasis on metals. It discusses the key concepts of elevated-temperature design. These include plastic instability at elevated temperatures; deformation mechanisms and strain components associated with creep processes; stress and temperature dependence; fracture at elevated temperatures; and environmental effects. The article describes the basic presentation and analysis methods for creep rupture. It provides information on the application of these methods to materials selection and the setting of basic design rules. The article examines the limitations of high-temperature components as well as the alternative design approaches and tests for most high-temperature components.

This article begins with a discussion of the basic fracture modes, including dimple ruptures, cleavages, fatigue fractures, and decohesive ruptures, and of the important mechanisms involved in the fracture process. It then describes the principal effects of the external environment that significantly affect the fracture propagation rate and fracture appearance. The external environment includes hydrogen, corrosive media, low-melting metals, state of stress, strain rate, and temperature. The mechanism of stress-corrosion cracking in metals such as steels, aluminum, brass, and titanium alloys, when exposed to a corrosive environment under stress, is also reviewed. The final section of the article describes and shows fractographs that illustrate the influence of metallurgical discontinuities such as laps, seams, cold shuts, porosity, inclusions, segregation, and unfavorable grain flow in forgings and how these discontinuities affect fracture initiation, propagation, and the features of fracture surfaces.