Experimental study about nano-deformation field near quasi-cleavage crack tip

Using the nano-moire method, we measure the near tip nanoscopic deformation on the {111} plane of single crystal silicon with a loaded quasi-cleavage crack running in the [110] direction. The measured strain distribution ahea d of the crack tip agrees with the linear elastic fracture mechanics predic tion up to 10 nm from the crack tip. Dislocations of Peierls type are detec ted and they extend from the crack tip over a length of hundreds of Burgers vectors.