_STP_436-1968.pdf

ELECTRON FRACTOGRAPHY A symposium presented at the Seventieth Annual Meeting AMERICAN SOCIETY FOR TESTING AND MATERIALS Boston,Mass.,25-30 June,1967 ASTM SPECIAL TECHN!CAL PUBLICATION NO.436 List price$11.00;20 per cent discount to members published by the AMERICAN SOCIETY FOR TESTING AND MATERIALS 1916 Race Street,Philadelphia,Pa.19103 BY AMERICAN SOCIETY FOR TESTIN AND MATERIALS Library of Congress Catalog Card Number:68-15547 NOTE The Society is not responsible,as a body,for the statements and opinions advanced in this publication.1968 Printed in Rahway,N.J.July,1968 Foreword The Symposium on Electron Fractography was presented during the Seventieth Annual Meeting of the Society held in Boston,Mass.,25-30 June 1967.The symposium was sponsored by Committee E-24 on Fracture Testing of Metals.The symposium chairman was C.D.Beachem,Naval Research Laboratory.Related ASTM Publications Techniques of Electron Microscopy Diffraction Microprobe Analysis,STP 372(1965),$3.75 Fracture Toughness Testing and Its Applications,STP 381(1965),$19.50 Advances in Electron Metallography,Vol.6,STP 396(1966),$7.00 Fatigue Crack Propagation,STP 415(1967),$30.00 Contents Introduction.1 Electron Fractography-Tools and Techniques-J.L.MC CALL 3 A Fractographic Analysis of the Relationships Between Fracture Toughness and Surface Topography in Ultrahigh-Strength Steels-W.A.SPITZIG,G.E,PELLISSIER,C.D.BEACHEM,M.HILL,AND W.R.WARKE.13 Discussion.30 Cleavage Phenomena and Topographic Features-H.C.BURGHARD,JR.,AND N.S.STOLOFF.32 Fracture by Microscopic Plastic Deformation Processes-c.O.BEACHEM AND D.A.MEYN.59 Application of Electron Fractography to Fatigue Studies-J.c.MC MIL-LAN AND R.W.HERTZBERG.89 Environmental Effects on Fracture Morphology-N.A.NIELSEN 124 Special Fractographic Techniques for Failure Analysis-B.V.WroTE-SON,A.PHILLIPS,V.KERLINS,AND R.A.RAWE.151 Engineering Applications of Fractography-A.j.BROTHERS AND S.YUKAWA.179 Fractography and Microstructure of Aluminum Alloys 7075-T651 and 7075-T7351-M.S.HUNTER AND J.C.MCMILLAN.196 Techniques for Electron Microscopic Fractography-w.R.WARKE,N.A.NIELSEN,R.W.HERTZBERG,M.S.HUNTER,AND M.HILL 212 STP436-EB/Jul.1968 Introduction The purpose of this symposium is to describe the present state-of-the-art of electron fractography,and report the results of activity sponsored by Subcommittee II on Fractography of ASTM Committee E-24 on Fracture Testing of Metals.It is hoped that future symposia on this subject will benefit from contributions from invited authors from laboratories throughout the world where excellence of electron fractographic usage in research and failure analyses has been proved.As the papers in the volume indicate,a great deal has been learned about the mechanisms of crack propagation,and the correlation of fine-scale fracture surface features with macroscopic stress and environ-ment conditions.This volume,however,does not cover all of the fractography sub-jects presently being studied,because tfiis tool is versatile and is being used to complement other research tools in a variety of disciplines.Neither have the subjects discussed herein been fully explored.There-fore,this volume should serve as a progress report,and one should ex-pect future symposia in electron fractography to include significant new applications of the tool and further refinements of existing theory and techniques.C.D.Beachem Head,Micro-Mechanical Metallurgury Section,Physical Metallurgical Branch,Metallurgical Div.,Naval Research Laboratory,Washington,D.C.;symposium chairman.Copyright 1968 by ASTM International 1 www.astm.org J.L.McCall a Electron Fractography Tools and Techniques REFERENCE:McCall,J.L.,Electron Fractography-Tools and Tech-niques,Electron Fractography,AS TM S TP 436,American Society for Test-ing and Materials,1968,pp.3-16.ABSTRACT:Electron fractography has recently become a valuable tool for studying the topographic features of fractures,and from it much new theoreti-cal and applied information regarding the micromechanisms of fractures has been obtained.Prior to the use of electron microscopes,the unaided eye,opti-cal microscopes,and metallographic cross sections were used to study frac-tures.These methods,however,have distinct limitations such as low resolution and small depth of field.Both of these limitations have been overcome with the electron microscope.Other tools are now being applied to fracture studies to complement the electron microscope.These include deep-focusing micro-scopes,electron microprobe analyzers,and scanning and reflection electron microscopes.The combination of all these tools has provided much new infor-mation,but it must be realized that electron microscopy as a tool for studying fractures is still essentially in its infancy,and it offers tremendous opportunities which,as yet,have not been fully explored.KEY WORDS:fractography,fracture,election microscopy Valuable information has long been known to exist in the fracture surfaces of materials,and,through the year