Fracture of Gd-2 (MoO4)(3) single crystals

Fracture behaviour of Gd-2 (MoO4)(3) Single crystal, which is improper ferr oelectric-ferroelastic, has been examined by means of point loading. There a re th ree fracture planes in gadolinium molybdat (GMO): {100} - main clea vage plane, {210} and {110} - secondary cleavage ones. It is shown that cra cks have a tendency to transit from secondary planes up to cubic plane and vice versa. This would be considered as the main cause of river pattern app earance on fracture surfaces of samples. Mechanical twinning and crack grow th are independent channels for relaxation of elastic energy in GMO, which do not connected between themselves, so excluding of twinning leads to incr ease of crack length. (C) 1999 Kluwer Academic Publishers.