Dislocation motion in erbia single crystals

Dislocation motion during high-temperature deformation of erbia single crys tals has been investigated. Compressive deformation alone [111], [(1) over bar (1) over bar 2], [(1) over bar 10] and [123] at 1640 degrees C resulted in slip on {110} planes. The Burgers vector was determined to be (b) over right arrow=1/2[1 (1) over bar 1]. Dislocations with such a large Burgers v ector (9.1 Angstrom), can dissociate into 1/4[1 (1) over bar 0] and 1/4(1 ( 1) over bar 2) partials. The critical resolved shear stress of the samples at 1640 degrees C was estimated to be approximate to 38 MPa. Cleavage at ro om temperature was found to be on {111} plants. (C) 2000 Published by Elsev ier Science S.A.