Phase decomposition in a B2-FeAl(Co) compound was investigated by means of transmission electron microscopy. The precipitation and hardening behaviors were investigated by measuring hardness variations. The disordered α-Fe phase was present as a precipitate in the B2-FeAl(Co) matrix, and had a cubic-cubic orientation with respect to the matrix. In the early aging period, prismatic dislocation loops formed in the B2-FeAl(Co) matrix. The loops had a Burgers vector of a<100>, and had the form of squares with their sides lying on the {100} plane of the B2-FeAl(Co) matrix. As the aging time was increased, the dislocation loops disappeared and α-Fe precipitates formed at the locations of the dislocation loops. The B2-FeAl(Co) matrix was typically hardened by the precipitation of α-Fe.

Dislocation Loops and Phase Decompositions of B2-FeAl(Co) Compound in the Fe-Al-Co Ternary System. W.H.Tian, M.Nemoto: Intermetallics, 2002, 10[7], 641-6