IRON- Binary Phase Diagrams Ortrud Kubaschewski Binary Phase Diagrams With a Preface by Oswald Kubaschewski With 103 Figures and 3 Tables 1982 Springer-Verlag Berlin Heidelberg GmbH Dr. rer.-nat. Ortrud Kubaschewski-von Goldbeck Lehrstuhl fUr Metallurgie der Kernbrennstoffe und Theoretische Hlittenkunde RWTH Aachen Kopernikusstrasse 16 D - 5100 Aachen Federal Republic of Germany ISBN 978-3-662-08026-9 ISBN 978-3-662-08024-5 (eBook) DOI 10.1007/978-3-662-08024-5 Library of Congress Cataloging in Publication Data Kubaschewski, Ortrud, 1922-. Iron - binary phase diagrams. Bibliography: p. 1. Iron. 2. Binary systems (Metallurgy). 3. Phase diagrams. 1. Title. TN693.17K84 1982 669'.961 82-10263 This work is subjected to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. U nder § 54 of the German Copyright Law where copies are made for other than private use, a fee is payable to 'Verwertungsgesellschaft Wort', Munich. © Springer-Verlag Berlin Heide1berg, 1982 Origina1ly published by Springer-Verlag Berlin/Heide1berg, and Verlag Stahleisen mbH, Diisse1dorf in 1982 Softcover reprint of the hardcover lst edition 1982 The use of registered names, trademarks etc. in this puclication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Offsetprinting and bookbinding: Konrad Triltsch, Wiirzburg 2060/3020-543210 Preface At the official dinner of a· meeting in May 1939, I was seated next to Max Hansen. When I congratulated him on the well deserved success of his "Aufbau der Zweistoff-Legierungen", he smiled: "yes, it was a struggle with the hydra, and so it has taken me seven years", meaning that whenever he had thought to have finished the phase diagram of a particular system, new evidence would turn up like the new heads of the Greek monster. There is no need to point out the importance of assessed phase diagrams to metallurgists or even anyone concerned with the technology and applica tion of metals and alloys. The information contained therein is fundamental to considerations concerning the chemical, physical and mechanical properties of alloys. Hansen's German monograph was followed by a revised English edition in 1958 with K. Anderko and the supplements by R.P. Elliott (1965) and F.A. Shunk (1969). All those who have made use of these volumes will admit that much diligent labour has gone into this work, necessary to cope with the ever increasing number of publications and the consequent improvements. In view of the large amount of experimental evidence it has become advisable to subdivide the subject matter and to deal with the binary phase diagrams of individual metals in turn. Mrs Kubaschewski had already elaborated the phase diagrams of a number of metals of interest to reactor technology for the International Atomic Energy Agency and then turned her attention to iron. I have been in the position to bear witness to the painstaking work that she has put into the construction of such diagrams shown on the fol lowing pages. A vast amount of experimental, often conflicting, evidence had to be sifted. Thoughts had to be exerted on the position and the limits of nearly every phase, the thermodynamic conditions being always ob served. And all this is presented in an improved form on so-called 'raster paper'. The phase boundaries are based mainly on the results of con ventional experimental methods, but there are certain boundaries which are better ascertained by thermochemical calculation. The author has taken this into account. It may well be asked whether in these days of thermochemical calcula tions of phase diagrams (e.g. CALPHAD), one might not store the relevant heat and entropy values of each phase on a computer and let this do the working out. This is certainly true for the evaluation of ternary and higher phase diagrams. However, the binary systems should be treated separately, namely in the way chosen here. In the earlier days when we developed the thermochemical method for describing equilibrium diagrams (in which, incidtmtally, Miss von Goldbeck was also involved), William Hume-Rothery would protest by saying: "you may be able to correct certain phase boundaries by calculation but you cannot predict the existence of inter metallic phases". This is correct, at least at the present state of knowledge concerning the causes of chemical stability of phases. One may add that thermochemical calculations cannot be based on the results of calorimetric and Gibbs energy measurements alone, in particular when the diagrams are more complicated. So I used to reply to Hum-Rothery that the real value of the thermochemical method lay in the possibility of extrapolating v Preface from the binary into the multicomponent ranges, whereas in the binaries it is merely used for adjustments. The problem of predicting phases that do not appear in the binary border systems becomes less and less prominent the greater the number of component elements there are per system. The reason for this is the increasing influence of the entropy of mixing which favours the stability of the disordered solutions and thus depresses (T!1S term!) the appearance of any ordered phase to lower, in practice less important, temperatures. I usually distinguish between 'phase diagrams' and 'equilibrium diagrams', the former being derived wholly from conventional measurements, the latter from thermochemical calculations. One may safely say that the present series of binaries approaches the status of equilibrium diagrams. Hence, I submit that the author has coped with the hydra and expect that many of these diagrams will remain valid in detail for quite a number of years to come. Aachen, May 1982 Oswald Kubaschewski Acknowledgements The author is most grateful to Prof. Dr. O. Knacke who offered her the hospitality of his laboratory and his assistance in many ways, to Prof. Dr. Drs. h.c. O. Kubaschewski for continued interest, advice and, in particular, for meticulously checking the English, to Dipl. Ing. R. Steffen for critically reading the manuscript, to Mrs. G. Stusser and Mrs. E. Klein who made such an excellent job in drawing the raster diagrams and to the Commission of the European Communities, Division Steel, without whose financial assistance this work could not have been accomplished. Ortrud Kubaschewski VI Contents Notation IX Introduction . 1 Fe-Ag Iron-Silver. 3 Fe-Li (Na, K) Iron-Alkaline Metals 4 Fe-AI Iron-Aluminium. · (Figs. 1-3) 5 Fe-Am Iron-Americium . 10 Fe-As Iron-Arsenic · (Fig. 4) . 10 Fe-Au Iron-Gold · (Fig. 5). 13 Fe-B Iron-Boron · (Fig. 6) . 15 Fe-Ba Iron-Barium 18 Fe-Be Iron-Beryllium · (Figs. 7, 8) 18 Fe-Bi Iron-Bismuth. 22 Fe-C Iron-Carbon · (Figs. 9-12) 23 Fe-Ca Iron-Calcium . 26 Fe-Cd Iron-Cadmium 26 Fe-Co Iron-Cobalt · (Figs. 13, 14). 27 Fe-Cr Iron-Chromium · (Figs. 15, 16). 31 Fe-Cu Iron-Copper · (Figs. 17-20) 35 Fe-Eu Iron-Europium 38 Fe-Ga Iron-Gallium . · (Figs. 21-24) 38 Fe-Ge Iron-Germanium · (Fig. 25) 43 Fe-H Iron-Hydrogen · (Figs. 26, 27) . 46 Fe-D Iron-Deuterium · (Fig. 28) 48 Fe-T Iron-Tritium · (Fig. 28) 49 Fe-Hf Iron-Hafnium. · (Fig. 29) 50 Fe-Hg Iron-Mercury. · (Fig. 30) 52 Fe-In Iron-Indium · (Fig. 31) 53 Fe-Ir Iron-Iridium · (Fig. 32) 55 Fe-La Iron-Lanthanum. · (Fig. 33) 57 Fe-Mg Iron-Magnesium . · (Fig. 34) 59 Fe-Mn Iron-Manganese . · (Fig. 35) 61 Fe-Mo Iron-Molybdenum · (Figs. 36-38) 64 Fe-N Iron-Nitrogen. · (Figs. 39, 40) . 67 Fe-Nb Iron-Niobium. · (Fig.41) 70 Fe-Ni Iron-Nickel · (Figs. 42-44) 73 Fe-O Iron-Oxygen . · (Fig.45) 79 Fe-Os Iron-Osmium . · (Figs. 46, 47) . 82 Fe-P Iron-Phosphorus. · (Figs. 48, 49) . 84 Fe-Pb Iron-Lead. · (Figs. 50, 51) . 87 Fe-Pd Iron-Palladium · (Fig. 52) 88 Fe-Pt Iron-Platinum. · (Fig. 53) 91 VII Contents Fe-Pu Iron-Plutonium · (Figs. 54, 55) . 94 Fe-R Iron-Rare Earth Metals (Figs. 56-68) 96 Fe-Ce Iron-Cerium · (Figs. 56, 57) . 97 Fe-Pr Iron-Praseodymium. (Fig. 58) 100 Fe-Nd Iron-Neodymium · (Fig. 59) 101 Fe-Pm Iron-Promethium · (Fig. 60) 103 Fe-Sm Iron-Samarium · (Fig. 61) 104 Fe-Gd Iron-Gadolinium . · (Fig. 62) 106 Fe-Tb Iron-Terbium . · (Fig. 63) 108 Fe-Dy Iron-Dysprosium. · (Fig. 64) 110 Fe-Ho Iron-Holmium · (Fig. 65) 111 Fe-Er Iron-Erbium · (Fig. 66) 113 Fe-Tm Iron-Thulium. · (Fig.67) 114 Fe-Lu Iron-Lutetium. · (Fig. 68) 116 Fe-Re Iron-Rhenium · (Fig. 69) 118 Fe-Rh Iron-Rhodium · (Fig. 70) 120 Fe-Ru Iron-Ruthenium . · (Fig. 71) 123 Fe-S Iron-Sulphur . · (Figs. 72, 73) . 125 Fe-Sb Iron-Antimony · (Figs. 74, 75) . 128 Fe-Sc Iron-Scandium · (Fig. 76) 131 Fe-Se Iron-Selenium · (Fig. 77) 133 Fe-Si Iron-Silicon · (Figs. 78, 79). 136 Fe-Sn Iron-Tin · (Figs. 80, 81) . 139 Fe-Sr Iron-Strontium 142 Fe-Ta Iron-Tantalum · (Figs. 82, 83) . 143 Fe-Tc Iron-Technetium. · (Figs. 84, 85) . 146 Fe-Te Iron-Tellurium · (Fig. 86) 148 Fe-Th Iron-Thorium . · (Fig. 87) 150 Fe-Ti Iron-Titanium . · (Figs. 88-90) 152 Fe-TI Iron-Thallium. 156 Fe-U Iron-Uranium. · (Figs. 91, 92) . 157 Fe-V Iron-Vanadium · (Figs. 93-95) 160 Fe-W Iron-Tungsten · (Figs. 96, 97) . 164 Fe-Y Iron-Yttrium . · (Fig.98) 168 Fe-Yb Iron-Ytterbium · (Fig.99) 170 Fe-Zn Iron-Zinc · (Figs. 100, 101) . 172 Fe-Zr Iron-Zirconium · (Figs. 102, 103) . 175 Appendix Table 1. Physico-chemical properties of the elements 179 Table 2. Structural types of elements and compounds 183 Table 3. Numerical differences between the Internatio- nal Practical Temperature Scale of 1968 and that of 1948 185 VIII Notation For the convenience of the reader, the following drawing indicates the various lines that are being used for the description of the phase boundaries in the diagrams of this monograph: assessed uncertain secondary reaction - . - . - . - magnetic transformation °C i.e. gap between horizontal and vertical line indicates: (solid) solubility unknown a (metal) pertaining to pure metal a-metal pertaining to solution in metal IX Introduction This monograph is concerned with the binary equilibrium diagrams of iron with all the elements of the Periodic Chart except the halogens. Innumer able publications concerning these diagrams are available, and here is an attempt to correlate and assess the literature data. The monograph may be to some extent incomplete, but it is hoped to be a help to all who have to deal with the metallurgy of iron and steel and even metallurgists in general. The procedure of compilation has been as follows. The starting point has naturally been the classic work of Hansen [A] with its successors published by Elliott [B] and Shunk [C]. The thermochemical tables of Hultgren et al. [D] have also frequently been consulted. From there on (say, 1967) the literature has been searched and recorded well into 1981. A series of reviews edited by Ageev, 1968 to 1977 [E], !;las been a great help, in particular with regard to those Russian publications on which to lay hands had been difficult. Since the number of pUblications concern ing the binary phase diagrams of iron is astronomic, a strict selection of references had to be made so as not to overload the text. Earlier publica tions (if not quoted) may be traced via the compilations just mentioned. Some of the recent publications may have been overlooked but others, if they are just repetitive, have been disregarded deliberately. The melting point of iron accepted here is 1,536°C, and the transforma tion temperatures are 911 °C and 1,392 °C, and these temperatures apply to all the phase diagrams to follow, original results being consequently adjusted where necessary. The ferromagnetic transformation has its maxi mum at 767-771 °C although the corresponding heat capacity versus tem perature hump is spread over a much wider range. These temperatures as well as those for the other elements (see Table 1, Appendix) are based on the International Practical Temperature Scale 1968, revised 1975 and denoted IPTS-68. Secondary reference points have been assessed and listed by Crovini et al. [F]. Other melting and transformation points are from Hultgren's compilation [D] (updated to IPTS-68, where necessary) and from more recent re-determinations quoted in the original literature. Unfortunate ly, many investigators do not state the temperature scale they have used. Table 1 (Appendix), in addition to the transition temperatures, also lists the relative atomic mass, crystal structure and density of the elements. The arrangement of the systems is the alphabetical order in terms of chemical symbols of the component elements except for the alkali metals (appearing under 'Alk') and the rare earth metals (Fe-R), and here Eu and Yb are exceptions in that they are listed in the normal alphabetical sequence. The Fe-R systems are discussed in the following sequence: Ce, Pr, Nd, Pm, Sm, Od, Tb, Dy, Ho, Er, Tm, Lu (see 'Contents'). It should be noted that the pertinent references are listed immediately at the end of the text for every system. Care has been taken to mention in the texts the modes of alloy prep aration and the purity of the component metals as quoted by the in vestigators. Unless stated otherwise, % always indicate weight percent. -SI units are used where applicable. 1 Introduction Compared with the earlier compilations, the following advances are claimed. Phase boundaries could be pursued to lower temperatures thanks to improved experimental methods and longer times of annealing. Partly, new data for the magnetic properties are included in the text and in the diagrams. The emphasis is still on results obtained by conventional methods. However, results of thermochemical calculations are taken into consider ation. (For a discussion of the thermochemical approach, see for instance [G].) This is particularly useful, no, indispensable when it comes to the extra polation of solid solubilities to lower temperatures or to the assessment of solidus curves which are prone to slow equilibration (e.g. Cr-Fe). It is generally more difficult to assess accurately the temperature and composition of solid-solid transformations because the differences in Gibbs energy, representing 'driving force', may be very small and the rates of equilibration consequently very slow. This is particularly true when a com pound exhibits two or three modifications of the Laves structures. These are so similar in co-ordination that little energy is needed for the re-arrange ment of the atoms. (See also [H].) Only stable phases are included in the diagrams-with a few exceptions (e.g. Fe-C, Fe-N). Martensitic transformations, metallic glasses and the so-called phases are not included but are occasionally mentioned in the (U text. In future works of this nature, it may be desirable to say more about metastable phases. However, since their number is infinite, it is difficult to see where to draw the line. Concerning the notation of phases, the one accepted by the majority of authors is also used here, but it should be borne in mind that it is some times controversial. Agreement will eventually be reached by general con sent but is not a matter for the present compiler. Greek letters are used to denote solid solutions. Intermetallic phases are designated by Greek letters or stoichiometric compositions or both. Since the present author has been asked to continue this work by up dating the binary phase diagrams of iron whenever desirable, she would be grateful for any reprints of new investigations pertaining to the subject matter of this monograph. The following references pertain to the above but will also appear in the following texts with their Latin capitals. References A Hansen, M.; Anderko, K.: Constitution of Binary Alloys. New York: McGraw Hill 1958 B Elliott, R.P.: Constitution of Binary Alloys, First Supplement New York: McGraw-Hill 1965 C Shunk, F.A.: Constitution of Binary Alloys, Second Supplement New York: McGraw-Hill 1969 D Hultgren, R.; Orr, R.L.; Anderson, P.D.; Kelley, K.K.: Selected Values of Thermodynamic Properties of Metals and Alloys. New York: Wiley 1963 and Supplements E Ageev, N.V. (Ed.): Phase Diagrams of Metallic Systems 1968-1977, Acad. Sci. USSR, Moscow 1979 F Crovini, L.; Bedford, R.E.; Moser, A.: Extended List of Secondary Reference Points. Metrologia 13 (1977) 197 G Kubaschewski, 0.; Barin, I.: Phase Equilibria in Condensed Systems. Pure Appl. Chern. 38 (1974) 469 H Elliott, R.P.: Trans. ASM 53 (1960) 321 2