Processing and Miniaturized Disk-Bend Testing of TiAl/NiAl Intermetallic Composites Produced by Cryogenic Mechanical Alloying

Prealloyed titanium aluminide and nickel aluminide powders have been processed by high energy milling at cryogenic temperatures. This results in stable intermetallic powder mixtures with a fine grain size. Consolidation of these powders by uniaxial hot pressing results in unusual intermetallic composites with unique microstructures and exceptionally high hardness. Materials produced are evaluated for toughness and related mechanical properties by miniaturized disk bond testing. Samples consolidated at high temperatures possessed exceptionally high hardness and low fracture toughness. This was attributed to the formation of ternary phases during consolidation.