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i NBS SPECIAL PUBLiCATION 564

BINARY PHASE DIAGRAMS OF TRANSITION ELEMENTS

jUN 2 5 raao BINARY PHASE DIAGRAMS OF TRANSITION ELEMENTS

Group B Group A Mn

GROUP B ELEMENTS

Os Co Rh

Mn Fe Co Ni

Tc Ru Rh Pd

Re Os Ir Pt

Ti V Cr

Zr NI\) Mo

Hf TiI W

Format:

3000 —

Laves-type phases

Sigma phases

A15-type phases

ceMn-type phases

Nomenclature*.

BOG — a FCC — 7 HCP - e

r

SYSTEMATIC RELATIONSHIPS AMONG BINARY PHASE DIAGRAMS OF THE TRANSITION

The existing compilations of binary phase diagrams generally dis- play each diagram on a separate page. The various systems are then arranged in alphabetical order. This format provides easy access

to the phase diagram for any given alloy system. The disadvantage of

this format is the user's difficulty in trying to see certain systematic

regularities among the various phase diagrams. These regularities originate from fundamental variations in the electronic structures of the constituent elements. It is helpful, therefore, to see the phase

diagrams arranged in a format based on the occurrence ot the constituent elements in the periodic table. This formal enables the user to quicl<ry recognize regularities in the occurrence of particular types of alloy phases v^^ith the same or closely-related crystal structures. The

user may also see other systematic variations— in the solid solubilities, perhaps, or in the solid-liquid equilibria. The accompanying color chart is intended to reveal such

systematic relationships. However, in order to keep the size of this

chart within a reasonable limit, it has been necessary to construct the

individual diagrams on a much smaller scale than those which appear

in the conventional publications, such as the compilations by Hansen.' Elliott.' and Shunts.', This significantly decreases accuracy, and

the use of this chart for quantitative purposes is not recommended.

The chart is intended as a supplement to conventional compilations

aiding in understanding the systematic behavior. This Chan is not intended to sen/e as a compilation of phase

diagrams since the scale of the diagrams is too small for accurate

quantitative observations. It is intended primarily to reveal systematic

relationships. These relationships underlie the various theories of afloy phase stability and can be quite useful in designing new alloys

lor practical applications. This chart divides the transition efements into two groups the dividing line occurs between the column of elements headed by Cr and the column headed by l»ln. This is a somewhat natural division

ELEMENTS

Elements occurring to the left of this line (designated as A-elements)

a crystallize ,n a body-centered cubic structure at some temfTe^u e

al c^vstll?ze ^n'r '°n^ °' (<^==iS"ated as B eSn s) ?ubiro? hfxagoTar

^'"^'^-P^^^^''" ^"-"-^ (tace-centereJ The chart contains phase diagrams only for those allov systems in- ZZ!Ta.T« °' ^^te"'^"' and a B- emen These diagrams are generally more complex and contain a orealer varietv of intermediate phases than those involving A A ^B B comWnaltons which generally form extended terminal solid solutions \S7SUu,'T.T " " °' best information available in 1979, but there is no guarantee that the source materials are com- ?i?be ob'ILined"; ""'t:- m

°' '° tTMohgina?sources

can be obtained from The National Bureau of Standards Technical Information and Publications Division, Washington Dc 20234 "The user IS urged to consult these references for quantifative data

Diagrams published for a particular binary system by various in- vestigators can conflict vi'ith one another, and a critical review of the published data is virtually indispensable. The three-volume HansenElliott-Shunk senes,''^'^ while outdated, Js an excellent source for

critical reviews, The composition and temperature scales adopted for all of the phase diagrams are shown on the chart with the color code used to identify intermediate phases with selected crystal structures. Phase

boundaries are generally drawn as solid lines for clanty, even when

these appear as broken lines in the original references. In some cases

lines appear which are not given in any ot the references. This is done

only when there is some reason to believe that such boundaries actually exist as, for example, in the extrapolation of known phase boundaries to lower temperatures. The chart contains no provision for phase diagrams ot technetium

since the data for such systems is presently very sparse. Otherwise.

the chart is nearly complete. This chart should be helpful to alloy designers and other users of phase diagrams and may stimulate work on the few remaining systems for which not even the most rudimentary outlines of a phase diagram are presently available. The publication of tnis chart has been supported by the National Institute of Dental Research (National Institutes of Health) under Research Grant DE05031. and by the National Bureau of Standards.

Richard f^. Waterstrat

Research Associate, American Denial Association Health Foundation,

National Bureau o( Standards, Wastiington, D,C, 20234 GENERAL REFERENCES

1 M Hansen and K, AncJefko. "Conslilution ol Binary Alloys," 1958, McGraw-Hill. New

Yorh, Of Business Growth Services, General Electric Co,. Scheneclad/, NY 12345.

2- R. J. ElliotI, iCiid, First Supplement,

3 F A, Shunk. ibid. Second Supplemeni.

U.S. DEPARTMENT OF COfvllVtERCE

Philip M. Klutznick. Secretary

Lulher H, Hodges, Jr., Oepuly Secretary Jordan J, Baruch, Assislani Secretary

lor Pfoduclivily, Technology and Innovation NATIONAL BUREAU OF STANDARDS

Ernest Ambler. Director

For sale by Ihe Superintendent ol Documents,

U.S. Governmenl Printing OKice, Washinglon, D C 20402

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NBS SPECIAL PUBLICATION 564

Issued May 1980