PREFACE TO THE THIRD EDITION The objective of Mechanical Metallurgy continues to be the presentation of the entire scope of mechanical metallurgy in a single comprehensive volume.Thus, the book starts with a continuum description of stress and strain,extends this background to the defect mechanisms of flow and fracture of metals,and then considers the major mechanical property tests and the basic metalworking processes.As before,the book is intended for the senior or first-year graduate-stu- dent level.Emphasis is on basic phenomena and relationships in an engineering context.Extensive references to the literature have been included to assist students in digging deeper into most topics. Since the second edition in 1976 extensive progress has been made in all research areas of the mechanical metallurgy spectrum.Indeed,mechanical behav- ior is the category of research under which the greatest number of papers are published in Metallurgical Transactions.Since 1976 the field of fracture mechan- ics has grown greatly in general acceptance.In recognition of this a separate chapter on fracture mechanics has been added to the present edition,replacing a chapter on mechanical behavior of polymeric materials.Other topics added for the first time or greatly expanded in coverage are deformation maps,finite element methods,environmentally assisted fracture,and creep-fatigue interaction. As an aid to the student,numerous illustrative examples have been included throughout the book.Answers have been provided to selected problems for the student,and a solutions manual is available for instructors.In this third edition, major emphasis is given to the use of SI units,as is common with most engineering texts today. I would like to express my thanks for the many useful comments and suggestions provided by Ronald Scattergood,North Carolina State University, and Oleg Sherby,Stanford University,who reviewed this text during the course of its development. xiii