New Intermetallic NiAl-(Cr,Mo,Re) High Temperature Materials for Advanced Energy Conversion Systems

Advanced NiAl-based high temperature materials are developed and characterized for applications in energy conversion systems. The intermetallic compound NiAl with B2 superlattice structure exhibits superior physical and high-temperature mechanical properties, and excellent oxidation resistance. Disadvantages of polycrystalline NiAl are the lack in plasticity and fracture toughness and room temperature and insufficient high temperature strength at temperatures above 800 °C. The refractory metals Cr, Mo, and Re form with NiAl quasi-binary eutectic systems which enable to produce metal fibres reinforced NiAl-based alloys by using directional solidification. These in-situ composites showing fine-grained and thermally stable microstructures possessing high-temperature strength, superior creep resistence and sufficient room temperature ductility.