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.

Modeling of structure formation in casting of alloys involves several length scales, ranging from the atomic level to macroscopic scale. Intermediate length scales are used to define the microstructure of the growing phases and the grain structure. This article discusses the principles and applications of the phase field method and the cellular automaton method for modeling the direct evolution of structure at the intermediate length scales, where transport phenomena govern the spatial and temporal evolution of the structure that involves nucleation and growth.

Computational modeling assists in addressing the issues of solid/liquid interface dynamics at the microlevel. It also helps to visualize the grain length scale, fraction of phases, or even microstructure transitions through microstructure maps. This article provides a detailed account of the general capabilities of the various models that can generate microstructure maps and thus transform the computer into a dynamic microscope. These include standard transport models, phase-field models, Monte Carlo models, and cellular automaton models.

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 reviews the various aspects of the simulation of solidification microstructures and grain textures. It describes the grain structures and morphology of dendrites or eutectics that compose the internal structure of the grains. A particular emphasis has been put on the simulation of defects related to grain textures and microstructures. The article provides information on the application of the most important simulation approaches and the status of numerical simulation.

When planning a corrosion-testing program, it is advisable to select the testing conditions carefully in order to produce ranking parameters with minimal influence from testing conditions while rich in engineering significance. This article provides a discussion on test objectives, metal composition and metallurgical conditions, test specimen preparation, and corrosion damage assessment. It describes a strategy for planning the design of controlled and uncontrolled factorial experiments. The article contains a table that lists the elements of an iterative process for the experimental design. It illustrates the experimental designs applied to corrosion testing.

This article demonstrates the depth and breadth of commercial and third-party software packages available to simulate metals processes. It provides a representation of the spectrum of applications from simulation of atomic-level effects to manufacturing optimization. The article tabulates the software name, function or process applications, vendor or developer, and website information.

This article examines the critical features of four key areas of modeling transport phenomena associated with casting processes. These include heat and species transport in a metal alloy, flow of the liquid metal, tracking of the free metal-gas surface, and inducement of metal flow via electromagnetic fields. Conservation equations that represent important physical phenomena during casting processes are presented. The article provides a discussion on how the physical phenomena can be solved. It provides information on a well-established array of general and specific computational tools that can be readily applied to modeling casting processes. The article also summarizes the key features of the conservation equations in these tools.

Modeling will help reduce machining problems and thereby enable more rapid introduction of high-performance materials and components. This article discusses the technical needs of aircraft engine and airframe structural components and modeling of heat-treat-induced residual stress by finite-element residual-stress analysis. It describes the two-dimensional (2-D) and three-dimensional (3-D) procedures involved in finite-element residual-stress analysis. The article deals with the 2-D and 3-D machining distortion validation on engine-disk-type components. It describes methods for obtaining machining-induced residual stresses, including detailed finite-element analysis of the cutting process, the simple fast-acting mechanistic model, and the semi-empirical linear stress model. The article concludes with information on the modeling benefits and implementation of modeling in a production environment.

This article summarizes the general fatigue and fracture properties of cast steels, namely, toughness, fatigue, and component design factors such as section size and discontinuities. It describes the various factors that influence fatigue of cast steels. These factors include section size, defect size, stress modes, and waveform types. The article discusses various fracture mechanics in cast steels: cyclic stress-strain behavior and low- and high-cycle fatigue life behavior; plane-stress fracture toughness; plane-strain fracture toughness; constant-amplitude fatigue crack initiation and growth; and variable-amplitude fatigue crack initiation and growth.

This article presents conservation equations for heat, species, mass, and momentum to predict transport phenomena during solidification processing. It presents transport equations and several examples of their applications to illustrate the physics present in alloy solidification. The examples demonstrate the utility of scaling analysis to explain the fundamental physics in a process and to demonstrate the limitations of simplifying assumptions. The article concludes with information on the solidification behavior of alloys as predicted by full numerical solutions of the transport equations.

This article provides an overview of the principle forms of corrosion that can occur on automotive aluminum components and offers general guidelines on how best to avoid these situations. It discusses the most common forms of aluminum corrosion such as stress-induced corrosion, cosmetic corrosion, crevice corrosion, and galvanic corrosion.

This article summarizes fatigue phenomena in metallic materials. It discusses fatigue under variable-amplitude (VA) loading, with emphasis on crack growth. The article presents the prediction models of crack initiation and crack growth under VA loading. It concludes with a discussion on the conditions associated with engineering applications of VA loading.

Thermomechanical are used to gain insight into the causes of problems that arise during a given thermomechanical process. This article provides examples to demonstrate how significant the parameters were selected for specific tests. It examines the types of problems that can occur during a thermomechanical process. The article provides information on the thermophysical properties, which include specific heat, coefficient of thermal expansion, thermal conductivity/diffusivity, and density. It concludes with examples that illustrate how the various considerations in testing are successfully used to solve practical thermomechanical processing problems.

The microstructure that develops during the solidification stage of cast iron largely influences the subsequent solid-state transformations and mechanical properties of the cast components. This article provides a brief introduction of methods that can be used for simulating the solidification microstructure of cast iron. Analytical as well as numerical models describing solidification phenomena at both macroscopic and microscopic scales are presented. The article introduces macroscopic transport equations and presents analytical microscopic models for solidification. These models include the dendrite growth models and the cooperative eutectic growth models. The article provides some solutions using numerical models to simulate the kinetics of microstructure formation in cast iron. It concludes with a discussion on cellular automaton (CA) technique that can handle complex topology changes and reproduce most of the solidification microstructure features observed experimentally.

In cast iron, residual stresses normally arise due to hindered thermal contraction, meaning that they are associated with the presence of constraints that prevent the natural, free volumetric variation of the material upon solid-state cooling. This article explains their mechanism of formation by introducing the scalar relation, known as the additive strain decomposition. The main factors influencing casting deformation are volume changes during solidification and cooling, phase transformations, alloy composition, thermal gradients, casting geometry, and mold stability. The article reviews the dimensional stability in cast iron and discusses macroscopic and microscopic stresses in cast iron.

In order to model macrosegregation, one must consider convection and the partitioning of segregating elements at the dendritic length scale. This article describes microsegregation with diffusion in the solid. It presents a continuum model of macrosegregation and illustrates the simulation of macrosegregation and microsegregation.

This article summarizes some 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 provides information on life assessment strategies and conceptually illustrates the interplay of nondestructive evaluation (NDE) and fracture mechanics in the damage tolerant approach. It presents information on probability of detection (POD) and probability of false alarm (PFA). The article describes the damage tolerance approach to life management of cyclic-limited engine components and lists the commonly used nondestructive evaluation methods. It concludes with an illustration on the role of NDE, as quantified by POD, in fully probabilistic life management.

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.