DEVELOPMENT OF HIGH-TEMPERATURE DISPERSION STRENGTHENING IN RAPIDLY QUENCHED AL-TI-X ALLOYS

A series of binary Al-Ti alloys and a range of Al-Ti-based ternary all oys containing additions of Ce and Ni have been produced by chill-bloc k melt spinning with a view to generating microstructures comprising a large volume fraction of finely and homogeneously dispersed, thermall y stable, intermetallic particles. The microstructures and thermal sta bility of these alloys have been examined using transmission electron microscopy and the ageing response of an Al-Ti-Ni alloy monitored usin g microindentation hardness measurements. It has been established that high temperature (300-400-degrees-C precipitation strengthening can b e achieved in alloys based on the Al-Ti-Ni system, through rapid solid ification and postsolidification heat treatment, and that rapidly quen ched Al-Ti-Ni alloys, with a weight ratio Ti:Ni in the range (3:1)-(4: 1), appear to have significant potential for applications involving el evated temperatures.