Diffusion-based microalloying of aluminium alloys by powder metallurgy andreaction sintering

A diffusion-based technique of microalloying aluminium powder metallurgy pr oducts was examined to expand the range of feasible alloying additions. The rmodynamic calculations and diffusion rates for several elements suggested that tin and silver were the most promising; these elements were successful ly alloyed into AA 2014 on both a macroscopic and a microscopic scale. The final microstructures were examined using X-ray diffraction, X-ray mapping and energy-dispersive electron probe microanalysis. Silver additions were h omogeneous throughout the alloy microstructure, whereas tin was concentrate d in intergranular regions only. The results suggested that the technique w as viable for a variety of microalloying elements. Also, the extent of allo ying was predicted reasonably well using a mathematical mass balance model. (C) 1998 Kluwer Academic Publishers.