This article provides general guidelines for casting design to provide progressive solidification, minimize heat concentration, eliminate cores, and prevent distortion. Casting design also affects tolerances. Casting tolerances depend on the alloy being poured, the size of the casting, and the molding method used. Designers can predict the effect of the design on the structure of the final part using solidification simulation models, namely finite element and finite difference models, and rapid prototyping. The article concludes with a short note on how the quality is assured in the foundry.

This article focuses on the intermediate length scales, where transport phenomena govern the spatial and temporal evolution of a structure. It presents the cellular automaton (CA) and phase field (PF) methods that represent the state of the art for modeling macrostructure and microstructure. The article describes the principles of the PF method and provides information on the applications of the PF method. The CA model is introduced as a computationally efficient method to predict grain structures in castings using the mesoscopic scale of individual grains. The article discusses the coupling of the CA to macroscopic calculation of heat, flow, and mass transfers in castings and applications to realistic casting conditions.

A key aspect of solidification process modeling is the treatment of the interface between the solidifying casting and the mold in which it is contained. This article begins with information on casting-mold interface heat-transfer phenomena. It describes practical considerations and methods for incorporating interface heat-transfer coefficient into models and for quantifying the heat transfer coefficient experimentally. The article concludes with information on the selection of the heat transfer coefficient for a given casting configuration.

The systematic study of microstructural evolution during deformation under hot working conditions is important in controlling processing variables to achieve dimensional accuracy. This article explains the microstructural features that need to be modeled and provides an outline of the principles and achievements of each of the various microstructural models, including black-box modeling, gray-box modeling, white-box modeling, and hybrid modeling.

Rapid solidification is a tool for modifying the microstructure of alloys that are obtained by ordinary casting. This article describes the fundamentals of the four microstructural changes, namely, microsegregation, identity of the primary phase, identity of the secondary phase, and formation of noncrystalline phases. It considers three factors: heat flow, thermodynamic constraints/conditions at the liquid-solid interfaces, and diffusional kinetics/microsegregation, to understand the fundamentals of these changes. These factors are described in detail.

This article begins with balance equations for mass, momentum, energy, and solute and the necessary boundary conditions for solving problems of interest in casting and solidification. The transport phenomena cover a vast range of length and time scales, from atomic dimensions up to macroscopic casting size and from nanoseconds for interface attachment kinetics to hours for casting solidification. The article describes how to determine which phenomena are most important at the particular length and time scale for the problem. It concludes with several examples of the application of transport phenomena in solidification, focusing in particular on microstructure formation.

This article describes the three solidification mechanisms of peritectic structures, namely, peritectic reaction, peritectic transformation, and direct precipitation. It discusses the theoretical analysis, which shows that the rate of the peritectic transformation is influenced by the diffusion rate and the extension of the beta-phase region in the phase diagram. The article provides information on peritectic transformations in multicomponent systems.

This article presents the governing equations for moving a solidification front, based on the balance of mass, momentum, energy, and solute. It reviews how material properties and geometry can be analyzed in the context of the governing equations. The article provides several example problems that illustrate how the hierarchy of time and length scales associated with transport leads to the important features of cast microstructures. It includes equations for estimating microsegregation in cast alloys.

Solidification is a comprehensive process of transformation of the melt of metals and alloys into a solid piece, involving formation of dendrites, segregation which involves change in composition, zone formation in final structure of the casting, and microporosity formation during shrinkage. This article describes the imperfections in the solidification process including porosity, inclusions, oxide films, secondary phases, hot tears, and metal penetration. It talks about the purpose of the gating system and the risering system in the casting process.

The modeling and simulation of texture evolution for titanium alloys is often tightly coupled to microstructure evolution. This article focuses on a number of problems for titanium alloys in which such coupling is critical in the development of quantitative models. It discusses the phase equilibria, crystallography, and deformation behavior of titanium and titanium alloys. The article describes the modeling and simulation of recrystallization and grain growth of single-phase beta and single-phase alpha titanium. The deformation- and transformation-texture evolution of two-phase (alpha/beta) titanium alloys are also discussed.

This article illustrates the simulation procedure of casting process. It describes important elements and points of the simulations. These include the setting of clear simulation objectives, selection of proper simulation code, hints in modeling of shape and phenomena, initial and boundary conditions, physical properties, enmeshing, and evaluation of simulation results. The article provides some insights into the application of models to real world problem for foundry process engineers.

This article explores the potential of through-process simulations of the development of microstructure, texture, and resulting properties during the thermomechanical processing of Al-Mn-Mg alloys, starting from the as-cast ingot to final-gage sheet. It provides an introduction of the thermomechanical production of aluminum sheet and, in particular, highlights the main effects governing the evolution of microstructure and texture. The simulation tools used to model the evolution of microchemistry, microstructure, and texture upon deformation and recrystallization of aluminum alloys are described. The article discusses the recrystallization behavior of alloy AA 3104 during the interstand times in between two consecutive hot rolling passes with the help of combined microstructure models.

This article discusses selected highlights of thermodynamic relationships during solidification and nucleation kinetics behavior in connection with the basis of nucleation treatments, such as grain refinement and inoculation, to provide a summary of nucleation phenomena during casting. Nucleation during solidification is a thermally activated process involving a fluctuational growth in the sizes of clusters of solids. The article describes nucleation phenomenon such as homogeneous nucleation and heterogeneous nucleation. It discusses various grain refinement models, such as carbide-boride model, free growth model, and constitutional undercooling model. The article concludes with a section on thermal analysis techniques for assessing grain-refining characteristics during master alloy processing.

This article summarizes some of the issues and approaches in performing computational analyses of mechanical behavior, distortion, and hot tearing during solidification. It presents the governing equations and describes the methods used to solve them. The article reviews the finite element formulation, multidomain approaches, and arbitrary Lagrangian Eulerian method in solidification modeling. It illustrates the sand casting of braking disks and continuous casting of steel slabs.

This article focuses on the concepts involved in heat-transfer modeling, thermomechanical modeling, and microsegregation modeling of hot tearing. It discusses the modeling of solidification defects, namely, inclusion entrapment, segregation, shrinkage cavities, gas porosity, mold-wall erosion, and hot-tear cracks.

This article outlines several polycrystal formulations commonly applied for the simulation of plastic deformation and the prediction of deformation texture. It discusses the crystals of cubic and hexagonal symmetry that constitute the majority of the metallic aggregates used in technological applications. The article defines the basic kinematic tensors, reports their relations, and presents expressions for calculating the change in crystallographic orientation associated with plastic deformation. It surveys some of the polycrystal models in terms of the relative strength of the homogeneous effective medium (HEM). The article analyzes the anisotropy predictions of rolled face-centered-cubic and body centered-cubic sheets and presents simulations of the axial deformation of hexagonal-close-packed zirconium. The applications of polycrystal constitutive models to the simulation of complex forming operations, through the use of the finite element method, are also presented.

Integrated computational materials engineering refers to the use of computer simulations that integrate mathematical models of complex metallurgical processes with computer models used in component and process design. This article outlines an example of a computer-aided engineering tool, such as virtual aluminum castings (VAC), developed and implemented for quickly developing durable cast aluminum power train components. It describes the procedures for the model development of the VAC system. These procedures include linking the manufacturing process to microstructure, linking microstructures to mechanical properties, linking material properties to performance prediction, and model validation and integration into the engineering process. The article discusses the benefits of the VAC system in process selection, process optimization, and improving the component design criteria.

This article provides a general introduction on casting processes and design. It discusses the process steps and methods of the main categories of shape casting methods, namely, expendable molds with permanent patterns, expendable molds with expendable patterns, and metal or permanent mold processes. The article lists general guidelines of geometry in casting design. It describes the factors, such as mold complexity and casting solidification, in casting design. The solidification of a casting can involve as many as three separate contractions as a result of cooling: liquid-liquid contraction, solid-solid contraction, and liquid-solid contraction. The article discusses the factors influencing the solidification sequence of simple shapes, such as T-sections, X-sections, and L-sections. It also provides an overview of geometric factors that influence heat transfer and transport phenomena. The article concludes with a description of the structure and properties of a casting.

This article discusses the two extremes of solute redistribution that results in microsegregation. The solute redistribution includes equilibrium solidification, nonequilibrium Gulliver-Scheil solidification, and nonequilibrium solidification with back diffusion. The measurement and kinetics of microsegregation are discussed for the binary isomorphous systems: titanium-molybdenum; binary eutectic systems: aluminum-copper and aluminum-silicon; binary peritectic systems: copper-zinc; multicomponent eutectic systems: Al-Si-Cu-Mg; and for systems with both eutectic and peritectic reactions: Fe-C-Cr and nickel-base superalloy.

Computational fluid dynamics (CFD) is a computationally intensive three-dimensional simulation of thermal fluids systems where non-linear momentum transport plays an important role. This article presents the governing equations of fluid dynamics and an introduction to the CFD techniques. It introduces some common techniques for discretizing the fluid-flow equations and methods for solving the discrete equations. These include finite-difference methods, finite-element methods, spectral methods, and computational particle methods. The article describes the approaches for grid generation with complex geometries. It discusses the four-step procedures used in the CFD process for engineering design: geometry acquisition, grid generation and problem specification, flow solution, and post-processing and synthesis. The article also provides information on the engineering applications of the CFD. It concludes with a discussion on issues and directions for engineering CFD.