HIGH-PERFORMANCE AEROSPACE ALLOYS VIA RAPID SOLIDIFICATION PROCESSING

Recent progress in the rapid solidification processing of metallic materials has opened new horizons for alloy design, expanding the ranges of possible microstructures and alloy compositions beyond those readily achieved through conventional technology. Alloy systems incorporating high volume fractions of ultrafine dispersed phases can now be produced, yielding corrosion and oxidation resistances and combinations of toughness and elevated temperature strength hitherto considered impossible. The particular examples discussed in this paper are those of high strength corrosion-resistant magnesium alloys, Al-Li alloys of reduced density, high temperature aluminum alloys and titanium alloys. In reviewing the design of these alloys, we discuss the interplay between the selection of alloy chemistry, the solidification kinetics characteristic of various rapid solidification powder production processes and the thermomechanical processing of the rapidly solidified powders. These three areas form links in a continuous chain, none of which can be neglected if the final product is to have the desired properties.