Microstructure and Mechanical Properties of NiAl Composites

The present research addressed the relationship between microstructure and mechanical properties of Al2O3-NiAl composites. From the experimental results of the composite inservice performance, i.e. long term thermal stability, properties after thermal cycling and creep behavior, important conclusions can be drawn on potential performance of the composites in gas turbine blades. Besides, the fiber fragmentation after specimen fabrication in the Al2O3-NiAl composites was the crucial factor to limit the mechanical properties of this composite. In order to solve the problem, it was attempted to modify the interface with damage-tolerant interlayers as well as to reinforce the NiAl alloy with ductile refractory Mo and Mo(La) wires.

In brief, a comprehensive characterization of NiAl composites was obtained in the present study; especially the creep performance of Al2O3-NiAl composites was determined for the first time. Based on the relationship between microstructure and mechanical properties, a model was proposed that successfully predicts the high temperature tensile strength of the Al2O3-NiAl composites. These achievements can serve as theoretical foundation and guidance to practical applications of NiAl composites as a core material in future turbine blades.