Crack nucleation in tungsten on crystallographic planes and on grain boundaries of twist misorientation

Cracks were induced in bicrystals of tungsten by an electrical discharge in paraffin oil at room temperature. The discharge led to local melting and evaporation of the metal, generating a crater solidification and subsequent shrinkage of the melted metal gave rise to high tensile stresses, promoting the formation of cracks along the cleavage planes 100 and 110 and grain boundaries of twist misorientation about the 100 and 110 lines. It is argued that the cracking of the high-angle boundaries may be due to the combined effects of favorable crack nucleation sites and reduction in surface-energy-dependent plastic work