CUBE PLANE SUPERDISLOCATION NETWORKS IN CREPT POLYCRYSTALLINE NI3AL

Polycrystalline Ni3Al with nominal composition 75at.% Ni-25at.% Al has been subjected to creep at 580-degrees-C under uniaxial compression a nd the dislocation structure examined by transmission electron microsc opy. A superdislocation interaction between the two screw superpartial pairs with perpendicular Burgers vectors, [101] and [101BAR], but whi ch share a common dissociation plane (010), leads to the formation of a node. Subsequently, superdislocation networks, which consist of an a rray of nodes on (010), form. A possible mechanism for the node format ion is discussed. The equilibrium shape of the superdislocation networ k has been estimated.