Abstract
A previous investigation of creep behavior in an Al-8.5Fe-1.3V-1.7Si (8009Al type) alloy processed by rapid solidification and strengthened with small incoherent Al₁₂(Fe,V)₃Si phase particles (Metall. Mater. Trans. A, 31A, 2000, p. 2229), is extended to temperatures ranging from 773 to 923 K using the isothermal constant-stress-creep test technique. While in the temperature interval 623-723 K the creep behavior of the alloy is associated with the true threshold stress, at 773-923 K the true threshold stress is absent: the apparent stress exponent of minimum creep strain rate, m_c, decreases with decreasing applied stress. Assuming a temperature independent value of the relaxation factor k_R characterizing the strength of attractive dislocation Al₁₂(Fe,V)₃Si particle interaction, an attempt is made to interpret the minimum creep strain rate behavior in terms of the Rosler-Arzt model (Acta Metall. Mater., 38, 1990, p. 67). The model fits the experimental creep data very well. The structure factor C following from the fitting procedure differs from that calculated from the structure data by a factor in average equal to ~60. The activation energy of detachment of dislocations from interacting Al₁₂(Fe,V)₃Si phase particles, following from the experimental creep data analysis, differs from that predicted by the model by a factor in average equal to 1.33. Thus, the thermally activated detachment of dislocations from the fine incoherent (interacting) particles is identified as the creep strain rate controlling process.

Key words
Al-8.5Fe-1.3V-1.7Si alloy, creep behavior, true threshold stress, load transfer effect

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