Plastic deformation of MgO(A12O2)1·1 spinel at 0·28TM preliminary results

Abstract

Prism-shaped single crystals of MgO(Al 2 O 3 ) n spinel (n < 1.1) have been compressed to significant plastic strain at a temperature of 400°C (∼0·28 T M ) in controlled experiments under a superimposed hydrostatic pressure of 1·4 GPa. Compression of crystals approximately parallel to <001>, <111> and <011> resulted in simple yield behaviour at axial stress differences of 1940, 3720, and 4300 MPa respectively. Well defined and broadly distributed slip lines on polished surfaces and stress-optical effects of slip bands have permitted identification of the following operating slip families: Typically, the members of the above slip families with the highest Schmid factors operated. Clear evidence for active cross-slip on the system {100}<110> was observed to nucleate from the {111}<110> slip bands in the ∼<011> specimen.