COMPUTATIONAL MATERIALS ENGINEERINGAn Introduction to Microstructure Evolution.This page doc

[...]... December 2006 xiii This page intentionally left blank 1 Introduction —Koen Janssens The book in front of you is an introduction to computational microstructure evolution It is not an introduction to microstructure evolution It does assume you have been sufficiently introduced to materials science and engineering to know what microstructure evolution is about That being said we could end our introduction here... straight to the computational chapters However, if you intend to learn more about the science of polycrystalline materials but want to learn about them through their computational modeling, then this chapter will give you the bare-bones introduction to the secrets of microstructures Just remember that the one law binding any type of computational modeling is equally valid for computational microstructure. .. Cantor view microstructures [MDC97]: a microstructure is a meta-stable structure that is kinetically prevented to evolve into a minimum free-energy 4 COMPUTATIONAL MATERIALS ENGINEERING configuration This means that to produce a specific microstructure, one must understand the kinetic path along which it evolves, and be able to stop its evolution at the right moment in processing time With the help of computational. .. CONTENTS xi This page intentionally left blank Preface Being actively involved since 1991 in different research projects that belong under the field of computational materials science, I always wondered why there is no book on the market which introduces the topic to the beginning student In 2005 I was approached by Joel Stein to write a book on this topic, and I took the opportunity to attempt to do so myself... growth Today, computational modeling is one of the tools at the disposal of scientific engineers, helping them to better understand the influence of different process parameters on the details of the microstructure In some cases such computational modeling can be useful in the optimization of the microstructure to obtain very specific material properties, and in specific cases modeling may be used directly to. .. 1.2 Microstructure Evolution Now that you have some idea of what microstructures are, we can start talking about microstructure evolution Evolution is actually an unfortunate word choice, as microstructures 1 A real material is always composed of a multitude of elements, leading to the saying that materials science is the physics of dirt” [Cah02]—but that is another story 2 COMPUTATIONAL MATERIALS. .. Doherty, and Cantor [MDC97] on the stability of microstructures, and Sutton and Balluffi [SB95] on interfaces in crystalline materials Finally, if you need decent mathematics to compute crystal orientations and misorientations, Morawiec’s work [Mor04] may help Introduction 5 1.4.2 On What Is Not Treated in This Book Unfortunately we did not have time nor space to treat all methods you can use for microstructure. .. random exchange of red and blue balls brings the system from an ordered state into a disordered state Experience tells us that the process never goes in the opposite direction In atomic diffusion, the probability of an atom to switch position with a particular neighbor is equal to the probability of the atom to switch back to the initial position in the following time step On a microscopic scale, diffusion... tends to reduce concentration gradients and thus brings the system into a state Thermodynamic Basis of Phase Transformations 19 with a higher degree of disorder If we bring NA moles of pure substance A into contact with NB moles of pure substance B, the irreversible process of diffusion of A atoms into the B-rich region and vice versa will finally lead to a homogeneous solid solution of A atoms and B atoms... hands in innocence 1.1 Microstructures Defined The world of materials around us is amazingly diverse It is so diverse that scientists feel the need to classify materials into different types Like the authors of this book, your typical technologist classifies materials based on their technical properties Fundamental groups are, for example, metals and alloys, ceramics, polymers, and biomaterials More specific . h0" alt="" COMPUTATIONAL MATERIALS ENGINEERING An Introduction to Microstructure Evolution This page intentionally left blank COMPUTATIONAL MATERIALS ENGINEERING An. 2006 xiii This page intentionally left blank 1 Introduction —Koen Janssens The book in front of you is an introduction to computational microstructure evolution.