Casting alloys of the Al–Ce–Ni system: microstructural approach to alloy design

The casting properties, microstructure, and mechanical properties at room and elevated temperatures were studied for Al–Ce–Ni alloys containing up to 16 wt.% Ce and 8 wt.% Ni. The alloys were cast at cooling rates ranging from 10−2 to 20 K s−1. The mechanical properties were considered in correlation with the structure formed upon solidification and high-temperature annealing. The ternary eutectic formed in these alloys was much finer than the binary eutectics and contained a high volume fraction of Al4Ce and Al3Ni. Annealing at 450°C led to a fragmentation and spheroidization of constituent particles in the ternary eutectics. The microstructure comprising fine globular aluminide particles uniformly distributed in the matrix resulted in maximum strength at room and elevated temperatures. Such a microstructure, formed in these alloys at relatively low cooling rates, is similar to that formed in rapidly solidified alloys. These aluminum-based multicomponent alloys with a microstructure containing complex eutectics produced by conventional casting are competitive with some RS–PM aluminium alloys and cast piston Al–Si alloys.