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This paper describes the light-microscopic observations of polystyrene latexes with spherical particles of two different diameters, d and 1.4-1.9d. Polystyrene latexes are available for simulating real structures in intermetallic compounds. An amorphous state appeared for a few hours after stirring or vibrating the latexes, and subsequently, the Laves phase structure nucleated and grew by the Brownian motion of the particles whose diameters were d and 1.4-1.7d. The structures of the observed Laves phase were classified into the MgCu2 and the MgZn2 types, containing such lattice defects as grain boundaries, dislocations, vacancies or mis-arranged particles.

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The process of order-disorder transformation during slow cooling and isothermal annealing in Fe–Al alloys has been investigated by means of X-ray diffraction. During slow cooling the ordering takes place through the two-phase state at a certain composition. while at other compositions it occurs as a single-phase transformation. The isothermal ordering proceeds by a nucleation and growth of the ordered phase, and under certain circumstances the precipitation of disordered phase takes place gradually in the course of annealing. The disordering into the two-phase state from an ordered single phase proceeds in two steps. The most plausible phase diagram of the Fe–Al system containing the two-phase regions, α+B2 and α+DO3, is proposed. The size of ordered domains is estimated from the widths of superlattice reflections, and its change during the order-disorder transformation is discussed.