The high temperature deformation of a rapidly solidified Al-10Fe-1.3V-2Si-1Ti-1W(wt. pct.) alloy was investigated by performing constant stress creep tests over the temperature range of 623K to 753K in the stress range 60MPa to 140MPa. The stress dependence of the steady state strain rates indicated a transition from diffusional creep to power law creep. The activation energy in the power law creep regime was close to that of bulk self-diffusion in aluminum, while the activation energy in the diffusional creep regime was close to that of grain boundary self-diffusion in aluminum.
In the Coble creep regime, it was found that the cell/subgrain boundaries are inefficient vacancy sources/sinks and that their contribution to Coble creep is totally suppressed in the alloy. The Coble creep rates could be explained by using the average diameter of the powder particles as the effective grain size in the Coble creep equation. The results were analyzed using the semi-empirical power law. It was proposed that the attractive dislocation-particle interaction originates from the dissociation of lattice dislocation into interfacial dislocations when they enter the matrix-particle interface at high temperature for climb by-pass. The semi-empirical power law with a threshold stress and a stress exponent of 5 was found to be representation for steady state creep of such alloys.
The attractive high temperature creep properties and stabilities of Al-10Fe-1.3V-2Si-1Ti-1W(wt. pct.) alloy are due to the high volume fractions of thermally stable spherical $Al_{12}(Fe,V)_3Si$ particles (30∼80nm diameter) uniformally distributed in an aluminum solid solution matrix with ultra-fine grain size (<1 microns). TEM was used to correlate creep deformation to microstructural and dispersoid parameters.