A study has been made of the initial stages of spinodal decomposition in a Cu-Ni-Fe alloy of composition close to the centre of the miscibility gap. During ageing the average wavelength can be accurately determined from a measurement of the sideband spacing along 〈100〉 on the diffraction pattern. The results obtained show that in this alloy decomposition occurs very quickly (e.g. in <10 s ageing at 600°C (873 K)) and the average wavelength follows a coarsening law (∞ t1/3) from the earliest time studied. The initial wavelengths found by extrapolation to zero time are of the order of 35–55 Å and vary with degree of undercooling below the spinodal in the manner predicted by theory.
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References
1.
HirschP. B., HowieA., NicholsonR. B., PashleyD. W. and WhelanM. J., “Electron Microscopy of Thin Crystals ”, Ch.14. 1965: London(Butterworths).
2.
ButlerE. P. and ThomasG., Acta Met., 1970, 18, 347.
3.
TannerL. E., Phil. Mag., 1966, 14, 111.
4.
HillertM., CohenM., and AverbachB. L., Acta Met., 1961, 9, 536.
5.
DanielV. and LipsonH., Proc. Roy. Soc., 1943, [A], 182, 378.
6.
HargreavesM. E., Acta Cryst., 1951, 4, 301.
7.
de FontaineD., “Local Atomic Arrangements Studied by X-Ray Diffraction"(edited byCohenJ. B. and HilliardJ. E.), p. 51. 1966: New York(Gordon and Breach).
8.
GreenwoodG. W., “ The Mechanism of Phase Transformations in Crystalline Solids” (Monograph and Report Series No. 33), p. 103. 1969: London(Inst. Metals).
9.
CahnJ. W., Trans. Met. Soc. A.I.M.E., 1968, 242, 166.
