High temperature creep behaviour of a Si3N4 whisker reinforced Al-Fe-V-Si composite

The creep behaviour of beta-Si3N4 whisker reinforced Al-8.5Fe-1.3V-1.7Si composite has been investigated at the temperature 773 and 823 K. The results are characterized by high stress exponent and high apparent creep activation energy. The creep data can be interpreted based on the incorporation of a threshold stress and a load transfer coefficient into the power-law creep equation. A good correlation between the normalized creep rate and normalized effective stress is available which demonstrates that the creep behaviour of both the alloy and the composite is controlled by the matrix lattice self-diffusion in Al. Examination on microstructure shows that edge dislocations exist at the interfaces between two adjacent whiskers and the interfaces emit edge dislocations in parallel paired-columns.