DENSIFICATION OF POROUS MATERIALS BY POWER-LAW CREEP

The densification of a porous intermetallic alloy (Ti-14wt%Al-21t%Nb) during the final stage of densification has been investigated under va rious states of stress and compared with the predictions of current mo dels for densification by power-law creep. The experiments generally c onfirm the model predictions that the densification rate is a sensitiv e function of the stress state. Experimentally, unconstrained uniaxial compression resulted in the largest densification rates, while constr ained uniaxial compression resulted in the lowest. Hydrostatic loading resulted in a densification rate similar (but slightly higher) than t hat of constrained compression. This ordering of the densification rat es agreed well with the model predictions. However, the magnitudes of the measured densification rates are found not to be accurately predic ted. A number of factors, including pore shape, pore spatial distribut ion and matrix microstructure have been observed to affect the densifi cation rate, and the significance of each of these factors to predicti ve modelling of creep consolidation processes is assessed.