Multiscale Phenomena In Materials Experiments And Modeling Related To Mechanical Behavior

The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners. This 2003 volume focuses on experimentally validated multiscale modeling of ductile metals and alloys.

In recent years there has been increasing interest in using what are termed 'multiscale modeling' approaches to understand the effects of composition and microstructure on mechanical behavior of materials. It is of utmost importance that these modeling efforts and simulations at the various length scales be coupled with experimental work. This 2003 volume focuses on experimentally validated multiscale modeling of ductile metals and alloys. The areas of atomistic, mesoscopic and continuum modeling are featured. Topics include: multiscale modeling of plastic deformation; dislocation phenomena at the atomistic-length scale; multiscale modeling of thin films and nanoindentation; multiscale modeling of dislocation phenomena and plastic deformation; multiscale modeling of microstructures and experiments; and models and experiments in nanostructured materials.

This book reviews the mathematical modeling and experimental study of systems involving two or more different length scales. The effects of phenomena occurring at the lower length scales on the behavior at higher scales are of intrinsic scientific interest, but can also be very effectively used to determine the behavior at higher length scales or at the macro-level. Efforts to exploit this micro- and macro-coupling are, naturally, being pursued with regard to every aspect of mechanical phenomena. This book focuses on the changes imposed on the dynamics, strength of materials and durability of mechanical systems by related multiscale phenomena. In particular, it addresses: 1: the impacts of effective dissipation due to kinetic energy trapped at lower scales 2: wave propagation in generalized continua 3: nonlinear phenomena in metamaterials 4: the formalization of more general models to describe the exotic behavior of meta-materials 5: the design and study of microstructures aimed at increasing the toughness and durability of novel materials

There has been increasing interest in using what are termed 'multiscale modeling' approaches to understand the effects of composition and microstructure on mechanical behavior. It is now quite common to find publications that report on related phenomena using atomistic, microscale (dislocation dynamics) and mesoscale/continuum computer simulations. With this enhanced interest in multiscale phenomena emerges a need for experimental work that validates and challenges the predictive capabilities of modeling and simulations. This book brings together experimentalists and modelers working in common areas of interest, to exchange information and lead to more tightly coupled experimental and modeling work. Topics include: plasticity at the continuum length scale; nonlocal plastic theory and dislocation phenomena; dislocation dynamics - experiments and simulation; dislocation core properties and effects; fracture and crack propagation; dislocation interactions with interfaces and grain boundaries; and microstructural modeling for industrial metals processing.

The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners.

A profusion of research and results on the mechanical behaviour of crystalline solids has followed the discovery of dislocations in the early thirties. This trend has been enhanced by the development of powerful experimental techniques. particularly X ray diffraction. transmission and scanning electron microscopy. microanalysis. The technological advancement has given rise to the study of various and complex materials. not to speak of those recently invented. whose mechanical properties need to be mastered. either for their lise as structural materials. or more simply for detenllining their fonnability processes. As is often the case this fast growth has been diverted both by the burial of early fundamental results which are rediscovered more or less accurately. and by the too fast publication of inaccurate results. which propagate widely. and are accepted without criticism. Examples of these statements abound. and will not be quoted here for the sake of dispassionateness. Understanding the mechanical properties of materials implies the use of various experimental techniques. combined with a good theoretical knowledge of elasticity. thermodynamics and solid state physics. The recent development of various computer techniques (simulation. ab initio calculations) has added to the difficulty of gathering the experimental information. and mastering the theoretical understanding. No laboratory is equipped with all the possible experimental settings. almost no scientist masters all this theoretical kno\vledge. Therefore. cooperation between scientists is needed more than even before.

In the past twenty years, new experimental approaches, improved models and progress in simulation techniques brought new insights into long-standing issues concerning dislocation-based plasticity in crystalline materials. During this period, three-dimensional dislocation dynamics simulations appeared and reached maturity. Their objectives are to unravel the relation between individual and collective dislocation processes at the mesoscale, to establish connections with atom-scale studies of dislocation core properties and to bridge, in combination with modelling, the gap between defect properties and phenomenological continuum models for plastic flow. Dislocation dynamics simulations are becoming accessible to a wide range of users. This book presents to students and researchers in materials science and mechanical engineering a comprehensive coverage of the physical body of knowledge on which they are based. It includes classical studies, which are too often ignored, recent experimental and theoretical advances, as well as a discussion of selected applications on various topics.