In situ observation of spinodal decomposition in In-35 at.% Tl-13.5 at.% Pb alloys

In situ observation of a spinodal decomposition in an In-35 at.% Tl-13.5% Pb alloys was made by transmission electron microscopy. When the alloy is aged at room temperature, the spinodal decomposition from fcc to f.c.t.(c/a > 1) + f.c.t. (c/a < 1) takes place, followed by the f.c.t.(c/a > 1) + f.c.t.(c/a < 1) → f.c.c.^* + f.c.t.^*(c/a > 1) separation. The in situ observation clearly confirmed that in the spinodal decomposition the formation of interfaces due to the growth of a compositional fluctuation takes place in an early stage and their disappearance in a later stage. Two types of elementary processes for the disappearance of the interfaces occur in the later stage. Further, both the power law for the increase in the wavelength, λ ∝ t ^{1 3}, and the dynamic scaling law for the space correlation function are found in the later stage on the analysis of the in situ observation. On the basis of the experimental results, the one-dimensional collision model is proposed for the later stage and further the frequency of the collision between a kink and an antikink, ω′, is shown to obey a power law of ω′ ∝ t^-1.