Hi I would like to have some infos on Silicon 111 crystal. I am looking around the web, the number for the fracture stress of silicon move from 7000 MPa to 1.2 MPa. Do you have some value for fracture stress of silicon thanks for your help Regards
I would hazard a guess that the critical resolved shear stress to fracture would be a better classifier parameter for brittle materials. The original poster mentioned silicon 111 crystal. Si is diamond cubic and the  planes would be the preferred slip planes.