Abstract
Creep behaviour of an Al-8.5Fe-1.3V-1.7Si alloy processed by rapid solidification is investigated at three temperatures ranging from 623 to 723 K. The measured minimum creep strain rates cover seven orders of magnitude. The creep behaviour is associated with the true treshold stress decreasing with increasing temperature more strongly than the shear modulus of aluminium. The minimum creep strain rate is controlled by the lattice diffusion in the alloy matrix and the true stress exponent is close to 5. The apparent activation energy of creep depends strongly on both applied stress and temperature and is generally much higher than the activation enthalpy of lattice self-diffusion in aluminium. Also the apparent stress exponent of minimum creep strain rate depends on applied stress as well as on temperature and is generally much higher than the true stress exponent. This behaviour of both the apparent activation energy and apparent stress exponent is accounted for by the strong temperature dependence of the treshold-stress-to-shear-modulus ratio. The true treshold creep behaviour of the alloy is interpreted in terms of athermal detachment of dislocations from fine incoherent
Al₁₂(Fe,V)₃Si phase particles admitting a temperature dependence of the relaxation factor characterizing the strength of the attractive dislocation/particle interaction.

Key words
Al-8.5Fe-1.3V-1.7Si alloy, creep, true treshold stress, true stress exponent, rate controlling process

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