The Design of Metallic Composites Made From Nickel Aluminide.

Abstract : The overall objective of this project was to design the microstructure and to test the fracture toughness and creep-rupture properties of metal-matrix composites constructed from NiAl and aluminum oxide. The goal has been to obtain a composite that not only has excellent high temperature creep properties, but also has good fracture toughness at room temperature. Principal microstructural variables have been (i) the crystallographic texture in the metallic phase, (ii) the bonding of the metal-ceramic interface, and (iii) the degree of interpenetration (percolation) of the phases, particularly the metal phase. The latter is greatly affected by the volume fraction of the ceramic phase, the metal ligament size constrained between the ceramic particles, and the grain size of the intermetallic phase.