XIV PREFACE TO THE SECOND EDITION 13 to Chapter 12. New discussions of fatigue crack propagation test techniques including computer control procedures, have been added to Chapter 13.This chapter also contains new examples of fatigue life calculations and an updated discussion of crack closure phenomena. a major new section has been added that deals with fatigue threshold testing and the consequence of short crack lengths on fatigue crack propa- gation(FCP)rates. Sections on load interaction effects, corrosion fatigue, and polymer tigue have been updated. The section on microstructural aspects of FCP has been expanded greatly to refect significant developments in this subject area during the past few years. Three new case histories involving fracture mechanics have been added to Chapter 14 along with a new section on typical defects found in engineering structures. Finally, Appendix A has been expanded to include sections on fracture surface preservation and cleaning techniques. The total number of problems at the end of each chapter has been increased by more than 50%. Seventy new figures and 280 additional references have also been added. About 70% of these references were published between 1977 and the present In an effort to update the book to the greatest extent possible, i sought the advic of numerous scientists and made extensive use of recent manuscripts that they pro- vided for my study. Many also took the time to review pertinent sections of the book and offered constructive criticism. To these colleagues, I offer my sincerest thanks These individuals include G. R. Yoder, P C. Paris, J. D Landes, K. Friedrich. I.J Mecholsky, C M. Rimnac, M. T. Hahn, R.S. Vecchio, C. Newton, C J. McMahon, Jr,F.P. Ford, R. P. Wei, N.E. Dowling, R Jaccard, R J. Stofanak, N. Fleck,R Bucci, R. O. Ritchie, S. Suresh, K. Tanaka, R. A. Smith, R. P. Gangloff, R D. Zipp, N.S. Cheruvu, J. A. Manson, G.P. Conard, IL,J. F. Throop, J. H. Underwood, JE Srawley, D. Hull, M. F. Ashby, D. Porter, V Hanes, and F. D. Lemkey My apologies to those whom I may have inadvertently failed to mention The manuscript was typed with considerable care by Louise Valkenburg, and Andrea Weiss provided excellent photographic assistance--I thank them both My wife, Linda, and my children, Michelle lyce and Jason Lyle, were very patient once again. Their sacrifices were great during this writing effort. I regret my periodic absence from family life, and I will try to make up for the lost time. Richard W. hertzberg
PREFACE TO THE FIRST EDITION This book discusses macroscopic and microscopic aspects of the mechanical behavior of metals, ceramics, and polymers and emphasizes recent developments in materials science and fracture mechanics. The material is suitable for advanced undergraduate courses in metallurgy and materials, mechanical engineering, and civil engineering a combined materials-fracture mechanics approach is stressed. The book als ill be useful to working engineers who want to learn more about mechanical met- allurgy and, particularly, the fracture-mechanics approach to the fracture of solids. I have assumed that readers have had previous training in strength of materials and basic calculus, and that they have been introduced to metallurgical principles including crystal structure. My objective is to make the reader aware of several viewpoints held by engineers and materials scientists who are active in the field of mechanical metallurgy: the crystal physics approach and the role of dislocations in controlling mechanical prop erties;the classical metallurgical approach, which stresses the relationship between microstructure and properties; and the fracture mechanics approach which describes he relationship between material toughness, design stress, and allowable flaw size. The application of each viewpoint in the analysis of certain mechanical responses of solids is illustrated, with the hope that the reader will soon recognize which approach might best explain a given set of data or a particular service failure. I think that unless a proper perspective is gained regarding the limits of applicability of the atomistic, microstructural, and continuum viewpoints the reader will become too involved in he fine points of a concept that may prove to be irrelevant to the problem at hand. Indeed, this is vital to a successful failure analysis The book is divided into two sections. Section One is devoted to a study of the deformation of solids. Here, emphasis is placed on the role of microstructure, crys- tallography, and dislocations in explaining material behavior. Section Two, the larger section, deals with the application of fracture mechanics principles to the subject of the fracture in solids. Although familiarity with some topics discussed in Section One will be useful to the reader, the information is not critical to an understanding of Section Two. Therefore the reader who wishes to focus on the subject of fracture can proceed from the introductory chapter on tensile behavior of solids( Chapter 1)directly to section Two Chapter 1 examines the different macroscopic mechanical responses of metals, ceramics, and polymers in relation to their respective tensile stress-strain response Chapters 2 to 5 constitute a closely related unit that deals with the deformation of crystalline solids. The elements of dislocation theory, discussed in Chapter 2, are source material for the discussion of slip and structure-property relationships in Chap-
XVI PREFACE TO THE FIRST EDTION ters 3 to 5. a detailed treatment of the crystallography of twinning is presented in Chapter 4 with an analysis of the cold-worked structure of crystalline solids in terms of mechanical fibering and preferred crystallographic orientations. To acquaint the reader with the multidisciplinary character of time-dependent, high-temperature creep processes in crystalline solids, the topics discussed in Chapter 5 include empirical creep strain relationships with time, temperature, and stress; parametric time-temper- ature relationships, such as the Larson-Miller parameter used in engineering materials design; and evaluation of creep strain dependence on such material properties as diffusivity, melting point, activation energy, grain size, crystal structure, and elastic modulus Superplasticity and deformation mechanism maps are also considered Sec- tion One concludes with a discussion of deformation in polymeric materials. Here again,the mechanical response of these materials is discussed both in terms of their continuum response(as described, for example, with linear viscoelastic relationships and mathematical analogs)and in terms of materials science considerations, involving such topics as the effect of structure on energy damping spectra and the micro- mechanisms of deformation in amorphous and crystalline polymers The subject of fracture is introduced in Section Two by a general overview, rangi from the continuum studies of Leonardo da vinci in the fifteenth century to current fractographic examinations that employ sophisticated transmission and scanning elec- tron microscopes. The importance of the stress intensity factor and the fracture me- chanics approach in analyzing the fracture of solids is developed in Chapter 8 and is compared with the older transition temperature approach to engineering design(Chap- ter 9), From this macroscopic viewpoint, the emphasis shifts in Chapters 10 and 11 to a consideration of the role of microstructural variables in determining material fracture toughness and embrittlement susceptibility Both environmental embrittle ment(such as stress corosion cracking and liquid metal and hydrogen embrittlement) nd intrinsic material embrittlement(such as temper, irradiation, and 300C embrit tlement) are described. The fatigue of solids is discussed at length in Chapters 12 and 13, and cyclic stress life, cyclic strain life, fatigue crack propagation philosophies, and test data are given. In the final chapter, actual service failures are examined to demonstrate the importance of applying fracture mechanics principles in failure anal ysis. Several bridge, aircraft, and generator rotor shaft failures are analyzed. In addi- ion, a checklist of information needed to best analyze a service failure is provided for use by the reader. This final chapter can be studied as a unit or as a source for pecific case histories that may be considered when a particular point is introduced n an earlier chapter. a number of scientific colleagues and former students provided valuable assistance in the planning and preparation of the book. since a complete listing of them would be too lengthy and vulnerable to inadvertent omissions, they cannot be cited individ- ually. I thank those who provided original prints of their previously published pho- ographs that enhance the technical quality of this book. I am grateful to my colle at Lehigh University for their many contributions and, most especially, to P C D. A. Thomas, Y. T Chou, J. A. Manson, M. R. Notis, N. Zettlemoyer, T. w.J.Mills, S. Siegler, B. Hayes, W. Walthier, and M. Skibo. The considerable care and exactness shown by Mrs. L. Valkenburg in typing the manuscript is deeply
PREFACE TO THE FIRST EDITTON XVIl ppreciated. I also thank the Alcoa Foundation and the Department of Metallurgy and Materials Science at Lehigh University for their financial support during the prepa ration of this manuscript. Finally, this volume, which is the most significant project in my teaching ca could not have been attempted or completed without the understanding and patience of my wife, Linda, and my children, Michelle Lyce and Jason Lyle. Their sacrifices were great; my gratitude is profound Richard w. Hertzberg July 1976
ABOUT THE AUTHOR ichard w. Hertzberg received his B S. cum laude in Mechanical Engineering from the City College New York, his M.S. in Metallurgy from M. IT. and his Ph D. in Metallurgical Engineering from Lehigh University. A recipient of two Alcoa Foun dation Awards of Outstanding Research Achievement, co-recipient of Lehigh Uni- versity's Award of Outstanding Research, recipient of Lehigh Universitys College f Engineering Teaching Excellence Award, and co-recipient of Lehigh Universitys award in Recognition of outstanding contributions to the University, Dr. Hertzberg has served as research Scientist for the United Aircraft Corporation Research Labs and Visiting Professor at the Federal Institute of Technology, Lausanne, Switzerland As an active member of several engineering societies, he has been elected as a fellow of the American Society for Metals. He has authored approximately 220 scholarly articles, co-authored Fatigue of Engineering Plastics(Academic Press, 1980), and completed the fourth edition of Deformation and fracture Mechanics of Engineering Materials. Dr. Hertzberg has also been an invited lecturer in the United States, Asia and Europe, and has served as a consultant to government and industry. Currently, he is New Jersey Zinc Professor of Materials Science and Engineering and Director of the Mechanical Behavior Laboratory of the Materials Research Center at Lehigh University