HVEMin-situobservation of anomalous (<ovl>1</ovl>01) slip in molybdenum

The behaviour of individual dislocations in high-purity Mo was observed continuously by in-situ deformation experiments in the high-voltage electron microscope. It is confirmed that two types of anomalous (low-stressed) slip are activated in Mo. One is the so-called (101) anomalous slip and is activated by a co-planar double slip (C.D.S.) mechanism. In this, primary a/2[111] screw dislocations react with a/2[111] screws to form the dislocation networks comprising the reactant a/2[111] and the product a[010] dislocations. The dislocation networks thus formed move as a whole on the (1101) anomalous slip plane, on which lie the Burgers vectors of the reactant and product dislocations, keeping the shape of networks. The other type of anomalous slip is activated by a surface-effect (S.E.) mechanism.