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Abstract

The transformation behaviour of a Ni–14·5 at.-%Ge alloy during aging has been studied using X-ray diffraction. Composition modulation is observed in the aged material and the wavelength of the modulation is found to increase with aging time. The increase in the composition modulation wavelength with time follows the Lijschitz–Slyozov and Wagner theory of diffusion controlled coarsening at 873 K. During the early stages of aging at 823 K the wavelength remains constant. The composition modulations due to spinodal decomposition lead to the formation of Ni₃Ge γ′ precipitates. An increase in hardness occurred before a significant amount of Ni₃Ge γ′ precipitated. This increase has been attributed to the composition modulation. In the later stages of aging, the increase in hardness is caused primarily by the Ni₃Ge precipitates.

MST/1735

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References

WEE

D. M.

, NOGUCHI

, OYA

, and SUZUKI

: Trans. Jpn Inst. Met., 1980, 21, 237.

and CHATURVEDI

M. C.

: Scr. Metall., 1991, 25, 405.

ARDELL

A. J.

and NICHOLSON

R. B.

: Acta Metall., 1966, 14, 1295.

and CHATURVEDI

M. C.

: Scr. Metall., 1992, 27, 247.

DANIEL

and LIPSON

: Proc. R. Soc., 1943, A181, 368.

DITCHEK

and SCHWARTZ

L. H.

: Acta Metall., 1980, 28, 807.

BULTER

E. P.

and THOMAS

: Acta Metall., 1970, 18, 347.

LIFSCHITZ

I. M.

and SLYOZOV

V. V.

: J. Phys. Chem. Solids, 1961, 19, 35.

WAGNER

: Z. Elektrochem., 1961, 65, 581.

10.

CAHN

J. W.

: Trans. Met. Soc. AIME, 1968, 242, 166.

11.

LAUGHLIN

D. E.

and CAHN

J. W.

: Acta Metall., 1975, 23, 329.

12.

MIYZAKI

, TAKAGISHI

, MORI

, and KOZAKARI

: Acta Metall., 1980, 28, 1143.

13.

LIVAK

R. J.

and THOMAS

: Acta Metall., 1971, 19, 497.

14.

CULLITY

B. D.

: in ‘Elements of X-ray diffraction’, 389; 1956, Massachusetts, Addison-Wesley.

15.

NASH

and NASH

: in ‘Binary alloy phase diagrams’, (ed. Massalski

T. B.

), 1974; 1990, Materials Park, OH, ASM.

16.

and CHATURVEDI

M. C.

: in Proc. 1st Pacific Rim Int. Conf. on ‘Advanced materials and processing’, 1992, The People's Republic of China (in press).

X-ray diffraction study of spinodal decomposition in Ni–14·5 at.-%Ge alloy

Abstract

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References