Dislocation loops and phase decompositions of B2-FeAl(Co) compound in Fe–Al–Co ternary system

Phase decompositions in B2-FeAl(Co) compound were investigated by means of transmission electron microscopy. Precipitation behavior and hardening were investigated by measuring the hardness variation. The disordered α-Fe phase is present as a precipitate in B2-FeAl(Co) matrix and has a cubic-cubic orientation with the matrix. At the early aging periods prismatic dislocation loops formed in B2-FeAl(Co) matrix. The loops have a Burgers vector of a<100> and have a shape of square with their sides lying on the {100} plane of the B2-FeAl(Co) matrix. As the aging time is prolonged, the dislocation loops disappear and α-Fe precipitates form at the locations of dislocation loops. B2-FeAl(Co) matrix is hardened typically by the precipitation of α-Fe.