Table of contents

We show how Monte Carlo simulations with the explicit interchange of atoms and the use of the semigrand-canonical ensemble, can be used to calculate phase diagrams for alloys. We illustrate our approach with the system Pd/Rh using the embedded atom method with potential parameters derived from ab initio density functional calculations. Our techniques take full account of local structural distortion, clustering and thermal effects.

Reliability of the potential functions under the condition far from equilibrium states, which is called transferability, is an important factor in the simulations of materials with nanoscopic complex structure under high stress condition. However, it has not been sufficiently investigated because it is difficult to get precise experimental data in such conditions. In this paper, simulations are conducted for aluminium bulk, grain boundary of aluminium and atomic chain under high strain using the potential function of the effective medium theory (EMT) as well as ab initio calculations in order to clarify the validity of EMT. In the cases of single crystal and the grain boundary under tensile strain, the results obtained from the EMT potential agree well with those obtained by ab initio analysis. However, the EMT cannot be applied to the atomic chain because the distribution of charge density differs significantly from that in the bulk.

To analyse the macroscopic and microscopic behaviours of heterogeneous materials and components, a multi-scale computational method is studied. Although asymptotic homogenization theory has been the main tool during the last decade to solve various multi-scale problems, the assumption of the periodicity of the microscopic unit cell and the incapability of considering the scale effect have resulted in the limitations to this theory's applications. These problems should be overcome because advanced materials are often used as joint or laminated components and the interface crack problem must be analysed. For this sake, a novel multi-scale finite element method is proposed that uses the enhanced mesh superposition method together with the asymptotic homogenization theory. The finite element mesh superposition method uses the global mesh and the local mesh that is superimposed arbitrarily onto the global mesh. The enhanced method allows the adoption of different constitutive laws for the two meshes. The advantage of the homogenization theory to predict the homogenized material model accurately based on the complex microstructure is still utilized. The homogenized material model is used for the global mesh, whilst the microscopic heterogeneity and the crack are considered in the local mesh with the material properties of the constituents. The formulation, modelling strategy, implementation and numerical accuracy of the proposed method is described. A porous ceramic is studied in the numerical example.

A new three-dimensional, random grid based cellular automaton model for the simulation of the evolution of a materials microstructure during recrystallization and grain growth is presented. The paper describes how the model can be linked to space and time coordinates and illustrates how theoretical analytical models describing grain boundary motion under the influence of a driving force can be used to control the cellular automaton. Simulation experiments illustrate the random grid base of the automaton eliminates the dependence of the model on the grid symmetry as observed in conventional cellular automata. Examples illustrating the correctness of the approach and its implementation are presented in the form of different verification experiments, including growth kinetics of a two different theoretical recrystallization processes, the shrinkage of a spherical grain driven by the curvature of its boundary and the evolution of the grain size distribution during grain growth in a polycrystalline microstructure.

AtomEye is free atomistic visualization software for all major UNIX platforms. It is based on a newly developed graphics core library of higher quality than the X-window standard, with area-weighted anti-aliasing. An order-N neighbourlist algorithm is used to compute the bond connectivity. The functionalities of AtomEye include: parallel and perspective projections with full three-dimensional navigation; customizable bond and coordination number calculation; colour-encoding of arbitrary user-defined quantities; local atomic strain invariant; coloured atom tiling and tracing; up to 16 cutting planes; periodic boundary condition translations; high-quality JPEG, PNG and EPS screenshots; and animation scripting. The program is efficient compared to OpenGL hardware acceleration by employing special algorithms to treat spheres (atoms) and cylinders (bonds), in which they are rendered as primitive objects rather than as composites of polygons. AtomEye can handle more than one million atoms on a PC with 1 GB memory. It is a robust, low-cost tool for surveying nanostructures and following their evolutions.

In this paper, the unsteady state heat transfer equations with time dependent boundary conditions are coupled with a two-dimensional finite element method to predict the work-roll temperature distribution during the continuous hot slab rolling process. To achieve an accurate temperature field, the effects of various factors including the thermal relationship of the work-roll and the metal slab, the idling work-roll revolutions, the rolling speed, the slab/roll interfacial heat transfer coefficient, and the magnitude of the thickness reduction of the slab at each deformation pass are taken into account. Comparisons between the predicted and published experimental results are used to illustrate the validity of the mathematical model.

This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis and simulation of polymers. The bibliography is an addendum to the Finite element analysis and simulation of polymers: a bibliography (1976–1996) published in the Modelling Simul. Mater. Sci. Eng.5 (1997) 615–50. The added bibliography at the end of this article contains 880 references to papers and conference proceedings on the subject that were published between 1996 and 2002. These are classified in the following categories: polymer flow and mixing simulation; polymer processing; thermal analysis of polymers; fracture mechanics of polymers; modelling polymer behaviours and their mechanical properties; practical polymer applications in engineering; other topics.

Effects of lateral heating on flow profiles and growth rates during the growth of mercurous chloride crystals by the physical–vapour-transport process in vertical ampoules are investigated by a two-dimensional model. The growth conditions of an experimental study available in the open literature are simulated. Lateral thermal boundary condition is modelled by a spatially sinusoidal heat flux. The results of the present computations are in agreement with the earlier experimental results and indicate that an increase in the lateral heating rate can cause a significant decrease in the transport rate while the flow accelerates. In the case of flow bifurcations, the growth rates can become as low as in the case of convectionless flow conditions.

This study focuses on modelling the behaviour of single crystal tantalum in Stage 0 characterized by the large activity of edge dislocations and relative inactivity of screw dislocations. The multiplication of dislocation density is investigated using dislocation dynamics (DD) simulations and a dislocation density based continuum model of single crystal plasticity. The DD simulations are used to guide the constitutive development of the continuum model and to determine its material specific parameters. While not all of the material constants needed by the continuum model can be determined, due to the limited strain histories considered in the simulations, interpreting the DD simulations through a dislocation mechanics based continuum plasticity model allows for the efficient extraction of scaling laws controlling the growth of dislocation density.