《物理化学实验》课程教学资源（书籍文献）二元合金相图 Binary alloy phase diagrams（Volume 1，Thaddeus B. Massalski，Joanne L. Murray Lawrence H. Bennett Hugh Baker）

Binary Alloy Phase Diagrams Volume 1 Editor-in-Chief Thaddeus B. Massalski Editors Joanne L. Murray Lawrence H. Bennett Hugh Baker Associate editor Linda Kacprzak Publisher William W. Scott, Jr. Assistant editors Benjamin P. Burton Terri Weintraub Judith Bhansali Graphics Editors Chery! E. Sirofchuck James S. Sims AS American Society for Metals Metals Park, Ohio 44073

Ka01+1534.424L3-s92CCopyright @1986byAMERICANSOCIETYFOR'METALSICTHTYTyFirst printing, Octdber 1986VSecond printing,AugMarep87AAHSPePdInB. NeNo part of this book may be reproduced, stored in a retrieval system, or tranamitted, in any form or by any means, electronic, mechanical, photocopying,recording,orotherwise,withoutthewrittenpermissionof thecopyrightowner.Great care was taken in the compilation and production of this volume, but it should be made clear that no warranties, express or implied, are givenin connection with the accuracy or completeness of this publication, and no responsibility can be taken for any claims that may ariseComments, criticisms,and suggestions are invited, and should be forwarded to American Societyfor Metals,Metals Park,Ohio 44073.TheNational Standard Reference Data System was established in 1963 for the purpose of promoting the critical evaluation and dissemination of numericaldata of the physical, chemical, and materials sciences.The NSRDS is coordinated by the Ofice of Standard Reference Data of the National Bureau ofStandards, but involves the efforts of many groups in universities, govermiment laboratories,and private industry.The primary aim of theNSRDS is toprovide compilations of critically evaluated physical and chemical property data needed by the scientific and engineering community. Activities carriedoutunder theNSRDSemphasize the evaluation of published data by scientistswho are experts in theresearch areas involved.The output of the International Data Program for Alloy Phase Diagrams, including the"Program" phase diagram evaluations contained in this compi-lation, has been reviewed by the Office of Standard Reference Data and accepted as a product of the Nationai Standard Reference Data System.DavidR.Lide,Jr.,DirectorStandard Reference DataNational Bureau of StandardsLibrary of Congress Cataloging-in-Publication DataBinary alloy phase diagrams.Bibliography: p.Includes indexes.I. Massalski, T.B1.Alloys.2.Phasediagrams.II.Murray, Joanne L.I. Bennett, L. H. (LawrenceHerman),1930IV. Baker, HughTN690.B528198686-17350669°.94ISBN 0-87170-261-4 (set)ISBN0-87170-262-2(v.1)SAN: 204-7586PRINTEDINTHEUNITEDSTATESOFAMERICA

NATIONALPROGRAMSINVOLVEDINBINARYALLOYEVALUATIONSASM/NBS Data Program for Alloy Phase DiagramsThe Indian Institute of Metals Committee on ResearchProgrammeforAlloyPhaseDiagramsCanadianPhaseDiagramResearchAssociationASM/NBSDATAPROGRAMSTAFFAmerican Society for MetalsManaging Director:Edward L.Langer*, Allan Ray PutnamTechnical Dircctor:William W. Scott, Jr.*, Allen G. GrayProgram Manager:Hugh BakerProduction Supervisor:Linda KacprzakProduction Coordinator:Suzanne Walker*,Carolee LiptonNational Bureau of StandardsDirector, Institute for Materials Science and Engineering:Lyle H. Schwartz*,Robert Mehrabian, John B.WachtmanChief,MetallurgyDivision:E.NevillePugh*,LouisR.Testardi,Robert Mehrabian,A. William RuffChief, Mathematical Analysis Division, Center for Applied Mathematics:Frederick C.Johnson*NBS Coordinator, Alloy Phase Diagram Program:James G.Early*,J. Beverley Clark* (Visiting Scientist), Gilbert M. Ugiansky,Kirit J. Bhansali, John R. CuthillEditor,Bulletin ofAlloyPhaseDiagrams:JoanneL.Murray*,Lawrence H. BennettAssociate Editors, Bulletin of Alloy Phase Diagrams:Benjamin P.Burton*,Daniel J. Kahan, Michael E. ReedEditorial Assistant:Rosetta V.DrewComputer Graphics and Database Development:DavidF.Redmiles,James S.Sims**,CarolineQualey**,Roseann Hayes,Donald J.Orser*At time of publication**ASM Research Associate at NBSEditorial AdvisoryCommitteeProfessor T.B. Massalski,Dr.J.D.LivingstonChairmanGeneral Electric Co., USACarnegie-Mellon University, USAProfessor R. MehrabianUniversity of California-Santa Barbara,Mr.H.Baker,USASecretaryDr. J.L, MurrayAmerican Society for Metals, USANational Bureau of Standards, USADr. K.J. BhansaliProfessorW.B.PearsonCabot Corporation,USAUniversity of Waterloo, CanadaDr. J.W.CahnDr.B.H.RosofNational Bureau of Standards,USAConsultant, Indianapolis,USAProfessor Y.A. ChangProfessor C.A. WertUniversity of Wisconsin-Madison, USAUniversity of Illinois, USA

Committee on Constitution of Binary AlloysProf.T.B. Massalski.Prof.L.BrewerDr.W.B,PearsonChairmanUniv.of California-Berkeley,USAUniversity of Waterloo, CanadaCarnegie-Mellon University, USADr. J.W.CahnProf. A.D. PeltonNational Bureau of Standards, USAUniversity of Montreal, CanadaMr.H. Baker,Dr. J.R. CuthillProf.J.H.PerepezkoSecretaryAmerican Society forMetals,USANational Bureau of Standards (Ret.), USAUniversity of Wisconsin-Madison, USAMr. A.PrinceDr. R.P. ElliottDr. I.N. AnsaraCleveland State University, USAGEC Research Laboratories, UKInst. Nat.Polytechnique, FranceProf. F.N. RhinesDr.K.A. Gschneidner, Jr.Dr.D.P. AntiaUniversity of Florida, USAIowa State University, USAIndustrial and ManagementProf. M. HillertDr. I.S. ServiConsultant, IndiaRoyal Institute of Technology, SwedenConsultant, USADr. L.H. BennettDr. J.L. MurrayDr. R.M. WaterstratNationalBureauofStandards,USANational Bureau of Standards, USANational Bureau of Standards, USADr.K.J.BhansaliProf. J.NuttingDr. J.H. WestbrookCabot Corporation, USALeeds University,UKKnowledge Systems,USACategory EditorsPlatinum-Group MetalsEditor-in-ChiefChromiumProf.T.B. MassalskiProf.J.P.NeumannDr.M.S.ChandrasekharaiahCarnegie-Mellon University,USAUniversity of Alabama, USABhabhaAtomicResearchCentre,IndiaCobaltUnaryRare-Earth MetalsProf.T.NishizawaProf. H.W. KingProf. K.A. Gschneidner, Jr.Tohoku University, JapanTechnical University of Nova Scotia,lowa State University, USACanadaCopperSilicon and GermaniumProf. D.E. LaughlinProf. C.B. AlcockProf. G.J.AbbaschianCarnegie-Mellon University, PA, USAUniversity of Toronto,CanadaUniversity of Florida, USAGallium, Indium, and ThalliumActinide MetalsSilverDr. IN. AnsaraDr.D.E.PetersonProf.M.R.BarenInst.Nat.Polytechnique, FranceLos Alamos National Laboratory, NMTemple University,PA, USAGoldUSAProf.W.T.ThompsonProf. T.B. MassalskiAlkali MetalsRoyal Military College, CanadaCarnegie-MellonUniversity,PA,USAProf. A.D.Pelton andSulfur, II-VI, III-VHydrogenProf.C.BaleProf.Y.A. ChangProf. G.C.Weatherly andUniversity of Montreal, CanadaProf.F.D.ManchesterUniversity of Wisconsin-Madison, USAAlkaline-Earth MetalsUniversity of Toronto, CanadaTantalumProf. C.B. Alcock andIronDr. R. KrishnanProf.V.P.ItkinDr.I..J.SwartzendruberBhabhaAtomicResearchCentre.IndiaUniversity of Toronto, CanadaNational Bureau of Standards, USATitaniumAluminumMagnesiumDr. J.L. MurrayDr. J.L. Murray andProf. J.B. ClarkNational Bureau of Standards, USADr. A.J. McAlisterUniversity of Missouri-Rolla, USANational Bureau of Standards, USATungstenMolybdenumDr.P.Rama RaoBerylliumProf.L.BrewerDefence Metallurgical Laboratory ofDr.L. TannerUniv.of California-Berkeley,USAIndiaLawrence Livermore NationalNickelLaboratory,CA, USAVanadiumProf.P.NashProf. J.F. SmithDr.H. OkamotoIllinois Institute of Technology, USAlowa State University,USALawrence Berkeley NationalNiobiumLaboratory, CA, USAZinc and CadmiumDr. E.-Th. HenigMax-Planck-Institut, Stuttgart, FR GerBoronDr.J.Dutkiewicz andDr.Z.MoserProf. K.E. SpearProf. J.F. SmithPolish Academy of SciencesPennsylvania State Univ.,USAlowa StateUniversity,USAZirconiumNitrogen and OxygenCarbonDr. H.A. WriedtDr.J.P.AbriataDr. H. HolleckArgentineAtomicEnergyCommissionNuclear Research Center, FR GerConsultant, USAiv

ASMResourcesCommitteeWilliam D. Manly,Dr. Jere H. BrophyDr. Richard K. PitlerTRW, Ine.Allegheny Ludlum Steel Corp.ChairmanCabot Corporation (Ret.)Kenneth J.BrondykePaul R. RoedelAluminumCompanyof AmericaCarpenter Technology CorporationDr. Raymond DeckerDr. E. Daniel AlbrechtDr. Morris A. SteinbergMichigan Technological UniversityBuehler LimitedLockheed Corporation (Ret.)Sponsors of theASMRestricted Principal FundPrincipal AssociatesFord Motor CompanyThe Aluminum Association, Inc.General Electric CompanyAmerican Iron and Steel Institute?General Motors CorporationOH.H. Harris Foundation.Battelle Memorial Institute?Cabot Corporation Foundation, Inc.oInterlake,IncCarpenter Technology CorporationLindberg CorporationCDefense Advanced Research Projects Agency (DARPA)Lithium Corporation of AmericaSHowmet Turbine Components Corporation9Lockheed CorporationIBM CorporationNational Forge FoundationInco Alloy Products CompanyPerkin-Elmer CorporationInco LimitedReading Alloys, Inc.9NASA--Lewis Research CenterRMI CompanyTeledyne, Inc.Special Metals CorporationOAssociatesOStandard Oil Company (Indiana)ASMMembers&ChaptersTIMET-Buehler LimitedTRW, Inc.GTE CorporationWyman-Gordon CompanyRaRockwell International CorporationContributorsAffiliates.Chase Brass and Copper Co.AlleghenyLudlum Steel Corporation.Detroit Chapter, ASMAllied CorporationInternational Metallographic Society:-American Welding and Manufacturing Co.9International Precious Metals Institute.Massachusetts MaterialsResearch,Inc./LehighTesting-ARCO Metals CompanyAT&T Bell Laboratories (EPRI)LaboratoriesaNorthrop Aircraft DivisionBrush Wellman Inc.?Mr. Adolph I. BuehlerPacker Engineering Associates, Inc.a.Electric Power Research Institute-Pittsburgh Chapter, ASMRolled Alloys, Ine.Fansteel, Inc.Sponsors of the CanadianPhase DiagramResearch Association FundAlcan International Ltd.9Energy,Mines,&Resources9AMCA InternationalSINCO Alloy ProductsOAtlas Steels.Norton Steel Co.Canada ForgingsOntario HydroC.ASM Chapters and MembersQuebec Iron and Titanium Inc..CanadianElectrical Association.Russell Steel Inc.DOFASCO Inc.Other Contributors of Support to Category EditorsAeronautics ResearchandDevelopmentBoard (India)Ministry of Science and Technology (India)1.Bhabha Atomic Research Centre (India)Molycorp Inc. (USA)9Comision Nacional de Energia Atomica (Argentina)National Science Foundation (USA)9-Defence Metallurgical Research Laboratory (India)NBS Office of Standard Reference Data (USA)?Department of Energy (USA)Office of Naval Research (USA).Engelhard Industries Ltd. (UK)Polish/US Joint Board of Scientific CooperationThe General Electric Co., p.l.c. (UK)Reactive Metals &Alloys Corp. (USA)Ronson Metals Corp. (USA)InternationalCopperResearchAssociationInternational Gold Corp. (RSA)Santoku Metal Industry Co., Ltd. (Japan)-Johnson MattheyPublic Limited Company (UK).Science and Engincering Research Council (UK)Max-Planck-Institut fur Metallforschung (FRG)Steel Authority of India Ltd. (India)Ministry of Education (India)Tata Iron and Steel Co., Ltd. (India)Ministry of Mines (India)V

Dr.Max Hansen1901-1978The first edition of Binary Alloy Phase Diagrams is dedicated to the memory of Dr.Max Asmus Karl Hansen (1901-1978), whosepioneering work in the compilation and evaluation of binary alloy phase diagrams,Der Aufbau derZweistofflegierungen,was publishedjust 50years ago.Dr.Hansen wil best be remembered not only for his 1936 publication, but also for the completely revised and enlarged second editionpublished in 1958,The Constitution of Binary Alloys, in colaboration with Dr.Kurt Anderko.The 1958 Handbook contained almosttwice the number of diagrams and references as the first edition and is considered of major importance to the metallurgical world. Itis the sole metallurgical reference among the25 scientific references most oftencited.Max Hansen was born January 27, 1901 in Bremerhaven. He became a student of Gustav Tammann, Professor and Director ofPhysical Chemistry at the University of Gottingen, who initiated much of the early work on phase diagrams. Dr. Hansen also had thedistinction of having Dr. Wilhelm Kroll, who developed the magnesium reduction process for making titanium, as chief sponsor forhis doctorate, which he received at the age of 23. From Tammann, he developed concern for phase diagrams, and early in his career,he completed a study of magnesium alloys,prepared a detailed critical review of the Cu-Zn system, and reported on the influence ofthird elements in brasses.While Head of the Metallurgical Research Department at Durener Metalwerke, A.G., Dr. Hansen produced his pioneering 1936Handbook.In 1936, he became Chief Metallurgist, and later Director and Vice President, of the Research Institute Berlin-Borsigwalde,where he published more than 20 articles dealing with aluminum alloy development, with emphasis on its use in aircraft construction.In 1947,Dr.Hansen accepted an invitation to teach at the llinois Institute of Technology.In 1949, he assumed duties at the IITresearchaffiliate,theArmourResearchFoundation(nowIlTResearchInstitute),wherehebecameManagerof theMetalsResearchDepartment.During this period, he worked on the second edition of his Handbook.He was also responsible for a numberof fundamentalphysical metallurgical studies and for the development of several new phase diagrams and alloys that have had a great impact on thetitanium industry.Dr.Hansen wrote more than 20 papers on the development of titanium and zirconium alloys.The Proceedings of the Second Inter-national Titanium Conference,held in 1972,werededicated to him in recognition of these contributions.After returning to Germany in 1954, Dr.Hansen served as Vice President and Technical Director of the Metallgesellschaft, A.G.until his retirement in 1966at age 65.He was Chairman of Deutsche Gesellschaftfur Metallkunde E.V.from 1956 to 1958 and in1963 received its Heyn Medal for his contributions to science. In 1964, Dr. Hansen was responsible for the organization of a series ofhighly successful symposia designed to bridge the gap between scientists and practical engineers. He was made an honorary memberof Deutsche Gesellschaft fur Metallkunde E.V.in i978, and in 1979, Dr, Hansen posthumously was made a Fellow of ASM, the firstcitizen of Germanyto hold this honor.Dr.Hansen carried a great deal of Tammann's initial work to completion and, like Tammann, developed many distinguished studentsof metallurgy. He taught, counseled, and stimulated his students and colleagues toward better, more productive careers and inspiredan esprit de corps in those with whom he worked.Dr.Hansen passed his excitement in the discovery of new facts about alloys to hiscolleagues, as well as hisperseverancein research.Keenly interested in the ASM/NBS Data Program, Dr. Hansen was one of the first members of the International Council. Hiscontributions and insight, even over a too-brief period, were invaluable to the Program. We trust that he would find this new com-pilation of evaluated binary alloy phase diagrams a fitting successor to his earlier work.It is indeed an honorto dedicate this reference book tohis memory,vi

ForewordIndustry and the scientific and engineering communities share the on-going challenge of more cost-effective produc-tion, increased research efficiency, and the need to clearly identify causes of material failures. To help meet thesechallenges, metallurgists and scientists must have ready access to the vast amount of phase diagram data being gen-crated. The American Society for Metals/National Bureau of Standards Data Program for Alloy Phase Diagrams wasestablished in 1978 to meet this need. It is an international effort, initiated and coordinated by ASM and NBS for thepurpose of critically evaluating all known phase diagram data for metallic systems and for disseminating assessed phasediagram dataAithough individual scientists had attempted various tasks toward this goal, critical evaluation of all metal combi-nations and an on-going, international organization to pursue this goal were vitally needed. The advent of the ASM/NBS Data Program for Alloy Phase Diagrams provided the needed foundation and support for continued research andcritical evaluation of phase diagramdata.Much of the impetus for the Program began in 1975, when the Numerical Data Advisory Board of the U.S.NationalAcademy of Sciences established The Ad Hoc Panel on Phase Diagrams for Alloys to look specifically at the needs forcritically evaluated alloy phase diagram data. The Panel noted that a successful program would truly have to be aworldwide enterprise-there was simplytoo much work forany one institution or organization,or even any country todo alone.The Panel recommended that an international counci be established to guide the development of the programand that the program deal not only with binary systems, but give priority to ternary and four-, five-, and six-componentsystems. They further recommended that the program develop a computerized bibliographic capability to aid in theprocess of locating phase diagram data among the published and unpublished literature from all over the world for usein critical evaluation.In addition,the Panel recommended that theprogram utilize computer technology to handle dataand, especially,to provide evaluated data in a useful form.In January of 1977, NBS responded to these needs with a workshop, inviting people from nine countries to talk aboutthe need for phase diagram data, both alloy and ceramic, and applications of these data. In June of 1977,ASM held ameeting to begin planning the eventual replacement of the phase diagram collection in the 8th Edition of Metals Hand-book. In February of 1978, after over a year of discussion and negotiations, a formal agreement was reached to proceedwith the ASM/NBSData Program for AlloyPhase Diagrams.ForASM, this was the largest and most important pro-gram of itskindeverundertaken.Thegoals of theData Program are:. Establishment of an organization and system within the Program to seek funding, determine priorities, and coor-dinate activities worldwide:Provision of critical evaluations of higher-order (ternary, ete.) systems, as well as binary alloy systems: Publication of evaluated diagrams and associated crystal structure and thermodynamic dataDevelopment and maintenance of a computerized databank containing the evaluated phase diagrams and associatedphase diagram data.Several groups and individuals played key roles in accomplishing these tasks. The International Council advises theData Program on its goals and operation. It is comprised of experts in alloy phase diagram compilation, evaluation, anduse, from industry and universities, The American Society for Metals operates the Program Office, which solicits andadministers funds to support development of the computerized database and evaluation projects in the United States.vi

It alsoprovides bibliographic support for evaluations,publishes complete evaluations in the Bulletin of Alloy PhaseDiagrams, operates the database, and acts as the central coordinating office of the Program. The National Bureau ofStandards comprises the Technical Office, which is concerned with all technical aspects of the evaluations, includingoperating model evaluation projects and technically editing publications.They are also responsiblefor the developmentof the computerized data handling, storage, and retrieval systems for the database.Overseeing the evaluation process are the Editors-in-Chief. Professor Thaddeus B. Massalski supervises activities inthe area of the elements and binary systems, and Mr. Alan A. Prince coordinates activities on the higher-order systems.Two Committees-the Constitution of Binary Alloys and the Constitution of Higher-Order Alloys-serve as advisorygroups for the Editors-in-Chief. Evaluation of individual alloy systems is the responsibility of Category Editors (forrelated groups of systems)and of Contributing Editors (for a few select systems).Category and Contributing Editorsare appointed by the Editors-in-Chief and include scientists who are recognized worldwide as experts in their respectivealloy systems, as well as in phase diagrams in general. Currently, there are over 40 Category Editors supervising ac-tivities in their respective areas of expertise. The exacting work of these Editors and their Co-Evaluators is the heartof theDataProgramFunding of the work of the Category Editors and their associates, as well as development of the computerized database,is essential to the progress of the Program. As its part of the funding effort, ASM undertook the raising of monies fora Restricted Principal Fund of $4,o00,0o0, which was generously contributed by industry,government,foundations,andASM Chapters and members, who recognized the importance and usefulness of the Program. Overseeing the solicitationof grants to the ASM Fund was the Resources Committee under the Chairmanship of Mr. William D.Manly.Vital alsoto the progress of the Program are those monies granted directly by other sources to the various evaluators and forother projects of the Program. Of special mention among these sources is the NBS Office of Standard Reference Data,especially its Chief, Dr.David R.Lide, Jr., and Program Manager,Dr. John R.Rumble, Jr., who have been supportiveof the Program by providing funds for the evaluation work of several Category Editors.Efforts currentiy are underway to further expand the international scope of the Program by more fully integratingthe ASM/NBS endeavor with those sponsored by scientific and engineering organizations in other countries to form atrulyinternationalProgram.This book was prepared under the ASM/NBS Data Program. It constitutes the most complete, reliable, and up-to-date reference on phase diagrams and associated data. For a list of all of the products currently available from theProgram, or for information on how to join or support this valuable worldwide venture, contact the Program Office atAmerican Society for Metals,Metals Park,OH 44073, USAE.L.LangerASMManagingDirectorvili

IntroductionIn order to utilize these volumes effectively, it is important for the user to have an understanding of how they were prepared, the style and conventions selected, and the standard values and nomenclature adopted for the various elementsand phases.Selection of Non-Program DiagramsDiagrams that had not been evaluated under the auspices of the Program were selected from previously publishedphase diagram assessments or compilations, such as Hansen, Elliott, Shunk, Kubaschewski, or Moffatt. Whenever pos-sible, diagrams that appeared to combine the most expert evaluation with the most up-to-date experimental data wereselected. Because the selection of diagrams did not involve re-evaluation of the data, the reader is cautioned againsttaking non-Program diagrams at face value, The original source and current literature should also be consulted.The two main criteria of selection--the depth of an evaluation and how recently it was published-often entailedarbitrary compromises. Clarity and consistency in the original diagram was also considered to be a factor. In a fewinstances, a more recent evaluation of a portion of a given phase diagram was grafted onto the phase diagram presentedin Hansen.Foralloy systems whereassessments areyet to bemade,diagrams were digitizedmostly from the compilationbyMoffatt.Diagrams available in published compilations in a substantially tentative form were replaced in the present yolumesby a short descriptive text (without a diagram) if the original diagram:. Showed only a series of stoichiometric compounds of unspecified decomposition temperaturesWas drawn or calculated purely on the basis of an analogy to a chemically similar system·Was inconsistent with the properties of the pure metals in a manner that could not be reconciled with established.data (for example, if complete solubility was shown between phases of different crystal structures or nonexistentpure metal phases). Was not drawn to any scale (completely schematic and/or speculative).Editing of theDiagramsEditing of non-Program diagrams was undertaken with two goals in mind--(1) the correction (when necessary) ofbasic errors of phase diagram construction and (2) standardization of pure element properties (number and structure ofstable allotropes, melting points, and allotropic transformation temperature), phase nomenclature, and style of presen-tation to agree with those established for the Program diagrams.Violations of the phase rule appeared in several guises, most commonly as invariant temperatures with two or fourphases in equilibrium. The digitization procedure required that the three phases in equilibrium at every horizontal beencoded in the data. Consequently, all errors of this kind have been uncovered and corrected.Diagrams in which a single-phase field encompasses phases of two different structures were harder to reconcile, be-cause the Editors did not feel justified in positioning phase boundaries arbitrarily.Another dilemma was presented bydiagrams that are, strictly speaking, thermodynamically incorrect, but which may nevertheless present the most faithfulportrayal of the experimental knowledge of some systems,notably those exhibiting polytypism.Previous compilationscontained many violations of the rule that, for two arbitrary phases (A and B), the A/(A + B) phase boundary cannotextrapolate into the single-phase A field at an invariant line. This error generally appears in the liquidus of systemsfor which only congruent melting points and invariant melting temperatures have actually been determined. For suchsystems, the liquidus boundaries were simply redrawn to be thermodynamically self-consistent.The label "?"on a diagram indicates a feature or point on the original diagram that the Editor was unable to interpret.In some instances,"!?" calls attention to features that are thermodynamically incorrect, but that the Editor could notcorrect in a straightforward manner.The pure metal transformation points were standardized for all diagrams, based on a list of temperatures approvedby the Category Editors. The list in effect on 1 April 1986 is accepted in the present volumes.For a few diagrams (Cr-based systems, for example), the original pure metal melting points were in error by as muchas 100 °C, in which case revisions of more than 50 °C in the liquidus would be required. It was considered preferabletoomittheaffectedliquidusboundariesentirelyRevisions of melting points in older diagrams caused the most problems when the change in the pure metal meltingtemperature was greater than the difference between the melting point and a eutectic or peritectic temperature asso-xi

Each Program entry in the present volumes consists of the "Assessed Phase Diagram," which has been digitized atNBS; a summary of the complete text published in the Bulletin (or submitted for publication); a crystal structure table;and a list of selected key references upon which the phase diagram has been based. The text summaries are limited inscope and attempt only to present the highlights of the complete evaluation. If the reader requires additional infor-mation, the complete published evaluation should be consulted.The entries prepared from Programevaluations are identified with the ProgramlogoProgramevaluationsthathave not undergone peer review by the time of this publication are labeled "provisional." These entries are expected tobe published in their entirety in future issues of the Bulletin of Alloy Phase Diagrams.Because much of the work in the Data Program is still in progress, non-Program sources were consulted to providea compendium of phase diagram data for binary systems not yet completed within the Program.Diagrams were firstselected from the existing published compilations (Hansen, Elliott, Shunk, and Moffatt, for example), but when a givenalloy system was unavailable in such a compilation, literature sources were used. In each case, the source selected isclearly identified under the diagram. In each case also, only the phase diagram has been reproduced, with a limitedguideto crystal structure data.Diagrams from sources other than the Data Program must not be regarded as "Assessed Diagrams" in the same senseas "Program" diagrams. This does not mean that such diagrams are less reliable, but only that they have not beensubjected to the same format of evaluation, or to the peer review, as in the Program, The reader is also advised to readcarefully the Introduction to the present volumes, where the handling of the non-Program entries is discussed further.In formatting the present reference volumes, the Editorial Advisory Committee recommended that the data and dia-grams be provided in a uniform fashion, thus making them useful for all applications. The Editors then undertook thisarduous task.The advisory committee also recommended that all the phase diagrams, both"Program"and"non-Pro-gram," be digitized and plotted by computer in uniform style and size for easier comparison. Furthermore, the diagramswere to be plotted in both atomic and weight percent, for the convenience of the user, and temperature values were tobe given in Celsius. (For the reader who uses the Fahrenheit temperature scale, a Celsius/Fahrenheit conversion tablehas been included in the Appendices.)Another recommendation made by the Editorial Advisory Committee was thatseparate overlay grids be provided for the phase diagrams, because the graphs would be too cluttered if grids weredrawn directly on the phase diagrams. However, because many different composition and temperature scales were usedin developing graphics for these volumes, individualized grids became impractical. Therefore, it was decided that aMaster Grid would be provided, from which a selected point of interest on the diagram could be estimated.Many decisions also had to be made concerning phase designations, nomenclature, etc. A well-known traditional pref-erence for alloy system identification emphasizesthemajorcomponent metal first.Forexample,theiron-carbon diagramis invariably displayed as Fe-C. A less obvious situation arises when both component elements are important in differentindustries, such as Si-Al or Cu-Be. Conventionally, phase diagrams of metals with metalloids or non-metals are dis-played with the metal on the left. In the present volumes, this trend has been followed.Also included in the present volumes are several Appendices of tabulated data on the pure elements, crystal structuredesignations, etc. These represent the latest compiled values and sources. Additionally, a comprehensive index of 3000binary alloy systems provides the classification of availablephase diagram information,thetype of information (diagramor text), and the original source of the material. This index also includes systems not covered in this first edition ofBinaryAlloyPhaseDiagrams.This great endeavor would not have been possible without the commitment, devotion, and very conscientious work ofmany people. Special thanks are due to all authors, to the Category Editors and Contributing Editors, to the professionalstaffs at ASM and NBS, to the members of the Advisory Committee, and to members of various sponsoring organizationsand their Committees for their contribution to this joint international effort. Their work, their professional backgroundand experience, and their enthusiastic commitment to the Phase Diagram Program have made this publication possible.May it serve all those who have need for it now and in the future, as well as those who have encouraged us to persist.T.B.MassalskiEditor-in-Chief