Nature of dislocation loops in electron-irradiated CuAuI and Cu3Au

Abstract

In CuAuI irradiated with 650 keV electrons at 300°C in a high-voltage electron microscope, six kinds of dislocation loops were found; their Burgers vectors and approximate habit planes are 1/2[01 1]/(010), 1/2[011]/(010), 1/2[101]/(100), 1/2[1101]/(100), 1/2[110]/(110) and 1/2[1 10]/(110). The first four kinds of loops are of the non-edge type, containing antiphase boundaries inside them, and the other two are of the pure-edge type and perfect in character. All loops are elongated in directions perpendicular to the c axis. No loops were found in grains oriented such that they were irradiated along [100], while numerous loops were found inside neighbouring twin-related grains oriented such that they were irradiated along [001]. Also, alignment of the loops at closely spaced twin interfaces in CuAuI and decoration of antiphase boundaries by Frank loops in Cu₃Au were observed.