PRODUCTION OF AL AL3TI COMPOSITES BY LOW-PRESSURE CASTING COMBUSTION SYNTHESIS PROCESS/

In order to get net-shape metal-matrix-composites, the LCCS process wh ich is the combination of low pressure casting and combustion synthesi s has been proposed. By this process, net-shape Al/Al3Ti MMCs, which c ontain few cavities, have been produced. Microstructures and mechanica l properties of the produced samples were examined. The effective infi ltration of molten Al into the Al-Ti mixed powders was observed at the Al mixing ratios higher than 50 at%. On the other hand, the Al mixing ratios less than 50 at% prevents the infiltration of molten Al. The c ritical mixing ratio, at which the infiltration can complete, is calcu lated by using a simple formula as a function of the relative density of Al-Ti mixed powders. In the mixing ratio of Ti powder less than the critical mixing ratio, the volume fraction of Al3Ti in the MMC increa ses with increasing Ti powder content.