Structure of Rapidly Solidified Al–(0.25–2.0) wt % Bi Alloys

Abstract

This article describes study of the microstructure and texture of aluminum alloy foils containing 0.25–2.0 wt % Bi and manufactured by high speed solidification. The cooling rate of the melt is at least 105 K/s. Aluminum texture (111) is generated in the foils. The average chord of cross sections of bismuth spherical precipitates does not exceed 0.5 μm. The size of dispersed bismuth particles increases and their number per unit volume of aluminum matrix decreases with increase in the distance to the foil surface. The specific surface area of interface boundary at first increases and then decreases upon movement of solidification front. The alloy foils are dissolved in water at ambient temperature, forming hydrogen bubbles and amorphous powder of Al2O3⋅5(H2O) and Al2O3⋅3(H2O) aluminum hydrides.