Abstract
Compressive creep of alloy based on Fe-30at.%Al with addition of 5.2 at.% zirconium was studied at temperatures from 650 to 900 °C. The alloy was tested in two different states: (i) cast and (ii) annealed at 1000 °C for 50 h. The microstructure of cast alloy consisted of matrix (α/B2/D03) and fine lamellar eutectic composed of λ₁ and (α/B2/D03). The eutectic decomposed during annealing at 1000 °C into λ₁ and τ₁ phases. Stress exponents and activation energies were estimated. The values of the stress exponent n can be explained by dislocation motion controlled by climb. The values of the activation energy in both cast and annealed alloy are greater than the activation enthalpy of diffusion. Creep exposure at 900 °C for about 50 h is probably sufficient for attainment the three-phase structure because the same microstructure was observed after creep at 900 °C, in both as-cast and annealed states. In contrast, creep expositions at 650 and 700 °C did not influence the appearance of microstructure.

Key words
iron aluminides, internal stresses, creep, precipitation

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