Creep in directionally solidified NiAl–Mo eutectics

A directionally solidified NiAl–Mo eutectic and an NiAl intermetallic, having respective nominal compositions Ni–45.5Al–9Mo and Ni–45.2Al (at.%), were loaded in compression at 1073 and 1173 K. Formidable strengthening by regularly distributed Mo fibres (average diameter 600 nm, volume fraction 14%) was observed. The fibres can support compression stresses transferred from the plastically deforming matrix up to a critical stress of the order of 2.5 GPa, at which point they yield. Microstructural evidence is provided for the dislocation-mediated stress transfer from the NiAl to the Mo phase.