Creep of three-phase alloy Fe-30%Al-5.2%Zr

0448410 - ÚFM 2016 RIV SK eng J - Journal Article
Dobeš, Ferdinand - Kratochvíl, P. - Kejzlar, P.
Creep of three-phase alloy Fe-30%Al-5.2%Zr.
Kovové materiály. Roč. 53, č. 3 (2015), s. 127-132. ISSN 0023-432X. E-ISSN 1338-4252
R&D Projects: GA ČR(CZ) GAP108/12/1452
Institutional support: RVO:68081723
Keywords : iron aluminides * creep * precipitation
Subject RIV: JG - Metallurgy
Impact factor: 0.365, year: 2015

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 τ 1 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.
Permanent Link: http://hdl.handle.net/11104/0250200