Transmission electron microscopy was performed to study the types of dislocations and their configurations in a commercially extruded ZK60 magnesium alloy. The weak-beam dark-field technique was mainly used, with a <01•0> zone axis, in order to unambiguously identify the Burgers vectors of various types of dislocation in the microstructure. It was found that non-basal 〈a〉 dislocations and 〈c〉 dislocations were predominant. No 〈c+a〉 was observed. Rearrangement of these dislocations, due to dynamic recovery during extrusion, led to cell walls and low-angle grain boundaries with relatively high density dislocations. Dissociation of the 〈c〉 dislocations with a relatively narrow split distance was observed. The dissociated 〈c〉 dislocations could form a nodular structure. Fringes of stacking faults from the dislocation dissociation were observed.

Dislocation Configurations in an Extruded ZK60 Magnesium Alloy. B.Li, E.Ma, K.T.Ramesh: Metallurgical and Materials Transactions A, 2008, 39[11], 2607-14