Download or read book Les m canismes de d formation d un acier TWIP FeMnC written by Jean-Louis Collet and published by . This book was released on 2009 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les mécanismes de déformation des aciers TWIP austénitiques Fe22Mn0.6C ont été étudiés par une analyse quantitative des profils des pics de diffraction aux rayons X. Les densités de dislocations et les probabilités de fautes d'empilement ont été déterminées en utilisant respectivement le modèle de Wilkens et la théorie de Warren. Cette approche de l'analyse des profils de raie a été modifiée pour prendre en compte l'effet des empilements de dislocations provoqués par le glissement planaire de celles-ci dans les métaux CFC à faible énergie de faute d'empilement. L'analyse quantitative du champ de contrainte moyen en tête des empilements de dislocations montre que celui-ci est égal au back-stress dans ces matériaux, ce qui nous a permis une mesure non destructive de celui-ci. Les résultats de cette méthode ont été confirmés à l'aide de l'indexation automatique de clichés de diffraction en microscopie électronique et de densités de dislocations mesurées par variation de la masse volumique issues de la littérature. Cette méthode a également été appliquée avec succès sur un échantillon standard, en l'occurrence un monocristal de cuivre. Nous avons confirmé que les mécanismes de déformation des aciers Fe22Mn0.6C, basés principalement sur la formation de martensite à très basse température, laissent place à un maclage intense à température ambiante puis au seul glissement des dislocations à haute température. L'analyse quantitative que nous avons développée a été également appliquée à des aciers TWIP Fe22Mn0.6C restaurés. La comparaison des mesures de densités de dislocations et du back-stress avec l'évolution de la contrainte d'écoulement durant le traitement thermique démontre clairement que le durcissement induit par le maclage n'est pas identifiable au back-stress.

Download or read book Diffusion in Materials DIMAT 2011 written by Igor Bezverkhyy and published by Trans Tech Publications Ltd. This book was released on 2012-04-12 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Conference on Diffusion in Materials (DIMAT) is the benchmark conference series for diffusion in solids. DIMAT 2011 was organized by the University of Bourgogne in association with CNRS, Dijon (France). The conference showcased new results concerning theoretical tools as well as applied research approaches. Diffusion processes affect all types of materials: nanomaterials, materials for energy, metallurgy, glasses and ceramics, but each requires its own numerical tools. Volume is indexed by Thomson Reuters CPCI-S (WoS). This volume comprises most of the contributions presented at DIMAT 2011: 4 plenary lectures delivered by famous high-level scientists plus 88 contributions in the form of keynote lectures, talks and posters.

Download or read book New Trends and Developments in Automotive System Engineering written by Marcello Chiaberge and published by BoD – Books on Demand. This book was released on 2011-01-08 with total page 681 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last few years the automobile design process is required to become more responsible and responsibly related to environmental needs. Basing the automotive design not only on the appearance, the visual appearance of the vehicle needs to be thought together and deeply integrated with the power developed by the engine. The purpose of this book is to try to present the new technologies development scenario, and not to give any indication about the direction that should be given to the research in this complex and multi-disciplinary challenging field.

Download or read book Nanodiffusion written by D.L. Beke and published by Trans Tech Publications Ltd. This book was released on 2004-01-01 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a contemporary overview of nanodiffusion, and details the present state of this rapidly growing field. New conceptions of basic aspects of the diffusion processes occurring at the nanoscale are treated, and many useful insights and results concerning diffusion kinetics in various types of technologically important nanomaterials are presented. The latter include: nanomagnetic materials, consisting of a mixture of magnetic nanoparticles in a residual amorphous magnetic matrix; thin films, bi-layers and multilayers for X-ray or neutron mirrors and for magneto-electronic applications such as GMR; and semiconductor nanosystems for many current and future applications.

Download or read book Continuum Models for Materials with Microstructure written by H.-B. Mühlhaus and published by . This book was released on 1995 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Continuum Models for Materials with Microstructure Edited by H. B. Mühlhaus, CSIRO, Nedlands, Australia When the characteristic length-scale (‘fabric dimension’) of the microstructure of materials is not small when compared to the macroscopic dimensions, the well established framework for the modelling of deformation processes for simple materials needs enhancement. To introduce an internal length scale, one has to resort to continuum models such as Nonlocal Theories, Cosserat or Gradient-type Models, Discrete Element and Lattice Theories or modified Viscoplastic Models. These new approaches are addressed in this volume. It includes contributions from research areas as diverse as bio-mechanics, concrete engineering and solid state physics. Generalised continuum models and its applications are presented and complemented by numerical and analytical tools for the solution of boundary value problems.