Role of interphase boundary adsorption in formation of spheroidal graphite in cast iron

Abstract

The interphase boundaries in grey and ductile cast iron were studied with a scanning Auger microprobe. Sulphur and oxygen were found to be adsorbed at the flake/metal interfaces in the grey iron, while the nodule/metal and intercrystalline graphite interfaces in the ductile iron were free of foreign elements. The only magnesium detected in the magnesium-modified ductile iron was combined with phosphorus and sulphur as a compound. A model is presented in which it is proposed that Fe–C–Si eutectic alloys in the absence of surface-active impurities (e.g. in vacuum casting o/high-purity materials) produce nodular graphite owing to the inherent instability of the graphite/melt interface. The sulphur and oxygen always present in commercial alloys adsorb at the graphite/melt interface, effectively ‘stabilizing’the active sites on the graphite basal planes, and preventing spherulitic growth. The purpose of modifiers is to getter these impurities.

Get full access to this article

View all access options for this article.

References

LUX

: Giessereiforsch. (in English). 1970, 22,158.

Lux

: ibid., 65.

BANNERIEE

: Br. Foundryman, 1965, 58, 344.

MORROGH

: Trans AFS, 1948, 56, 72.

MERCHANT

H. D.

: ‘Recent research on cast iron‘, (ed. Merchant

H. D.

), 33; 1968, New York, Gordon and Breach.

BUTTNER

F. H.

et al.: Am. Foundryman, 1951. 20, (10), 49.

MINKOFF

and LUX

: AFS Cast Metals Res. J., 1970,6, 181.

SAWYER

J. C.

and WALLACE

J. F.

: ibid., 1969,5, 83.

MCSWAIN

R. H.

et al.: ibid., 1974, 10, 181.

10.

WELD

H. M.

et al: J. Met., 1952, 4, 738.

11.

SPINDLER

W. A.

and FLINN

R. A.

: Trans A FS, 1962, 70, 1017.

12.

VANROOYEN

G. T.

and PAUL

: Met. SC., 1974,8, 370.

13.

JOHNSON

W. C.

et al.: Scr. Metall., 1974, 8, 1309.

14.

JOHNSON

W. C.

and smAim

H. B.

: ibid., 1975, 9, 1205

15.

JOHNSON

W. C.

and SMARTT

H. B.

: Metall. Trans. 1977, 8A, 553

16.

SMARTT

H. B.

et al.: unpublished research.

17.

JOHNSON

w. C.

and STEIN

D. F.

: Metall. Trans., 1974,5, 549.

18.

STEIN

D. F.

et al.: Can. Met. Q., 1974, 13, 79.

19.

JOSHI

and STEIN

D. F.

: Metall. Trans., 1970, 1,2543.

20.

MCDONALD

N. C.

et al.: Res. Develop., 1976, 27, (8), 42,48, 50.

21.

CHANG

C. C.

: Surf Sc., 1971,25, 53.

22.

JOHNSON

W. C.

et al.: Can. J. Spectroscop., 1972, 17, 88.

23.

WEHNER

G. K.

and HAJICEK

J. S.

: J. Appl. Phys., 1971,42, 1145.

24.

WENNER

G. K.

: ‘Methods and phenomena I — methods of surface analysis‘, (ed. Czandrna

A. W.

); 1975, New York, Elsevier Scientific Publishing.

25.

WAGNER

C. D.

: Anal. Chem., 1975, 47, 1201.

26.

MINKOFF

and NIXON

w. c.

: J. Appl. Phys., 1966, 37, 4848.

27.

VON

WARBICHLE

and GEYMAYER

: Giessereiforsch., 1973, 25,29.

28.

KEITH

H. D.

and PADDEN

F. J.

, JR:J. Appl. Phys., 1964,35, 1270

29.

KEITH

H. D.

and PADDEN

F. J.

JR : ibid., 1286.

30.

KEITH

H. D.

and PADDEN

F. J.

JR : 1963, 34, 2409.

31.

CHERNOV

A. A.

: Soy. Phys. Cryst., 1972, 16, 734.

32.

MULLINS

W. W.

and SEKERKA

R. F.

: J. Appl. Phys., 1963,34, 323.

33.

HULTGREN

et al.: ‘Selected values of the thermodynamic properties of binary alloys’, 485; 1973, Metals Park, Ohio, American Society for Metals.

34.

UBBELOHDE

A. R.

and LEWIS

F. A.

: ‘Graphite and its crystal com-pounds‘, 58; 1960, Oxford, Clarendon Press.

35.

GOLDSMITH

et al.: ‘Handbook of thermophysical properties of solid materials, revised edition —Vol. I: Elements’, 105, 115; 1961, New York, Macmillan.

36.

GOLDSMITH

et al.: ibid. 357.

37.

GOLDSMITH

et al.: ‘Handbook of thermophysical properties of solid materials, revised edition — Vo1.11: Alloys’, 64; 1961, New York, Macmillan.

38.

TOULOUKIAN

Y. S.

et al.: ‘Thermal conductivity — metallic elements and alloys’, 1128; 1970, New York, Plenum Press.

39.

ROSCOE

et al.: J. Mater. Sc., 1971, 6, 998.

40.

FRANK

F. C.

Disc. Faraday Soc., 1949, 5, 48.

41.

CHERNOV

A. A.

: Sov. Phys. Uspekhi, 1961, 4, 116.

42.

Lux

: AFS Cast Met. Res. J., 1972, 8, 49.

43.

Lox

et al.: ‘The metallurgy of cast iron‘, (eds. Lux

, Minkoff

, and Mollard

), 475; 1975, St. Saphorin, Switzerland, Georgi Publishing Co.

44.

HELLAWELL

: personal COInInUniCatiOn.

45.

HUNTER

M. J.

and CHADWICK

G. A.

: J. Iron Steel Inst., 1972, 210, 117.

46.

BLIZNAKOV

: J. Phys. Chem. (Leipzig), 1958, 209, 372.

47.

CHERNOV

A. A.

: Soy. Phys. Dok., 1960, 5, 654.

48.

CHERNOV

A. A.

: ibid., 470.

49.

THOMAS

P. M.

and GRUZLESKI

I. E.

: J. Iron Steel Inst., 1973, 211, 426.

50.

HONMA

and MINATO

: ‘mono (J. Jpn Foundryincites Soc.), 1959, 31, 1064.

51.

SADOCHA

J. P.

and GRUZLESKI

J. E.

: ‘The metallurgy of cast iron’, (eds. Lux

, Minkoff

, and Mollard

), 443; 1975, St. Saphorin, Switzerland, Georgi Publishing Co.

52.

4.1. LALICH: ibid., 561.

53.

WILSON

w. c.

et al.: J. Met., 1974, 26, 14.