Notched Cu bicrystals in compact tension shape made out of spark machining were tension tested. Specimen surfaces near notch tips were examined by optical microscope. The plastic zone developed as assembled fan-shaped sectors, the details of which depends on the crystal orientation of bicrystal. A sector is often characterized by a family of dominant slip lines.
The above experimental results about near notch tip plasticity in Cu bicrystals can be predicted by combination of latent hardening effect and resolved shear stress for each slip system calculated under the assumption of an isotropic continuum.
By step loading method slip lines developing firstly were detected. Depending on the Bi charging method a crack was initiated and propagated producing slip lines just near crack tip in the Σ5 bicrystal.
