AN EXPERIMENTAL STUDY OF THE PLASTIC STRAIN FIELDS NEAR A NOTCH TIP IN A COPPER SINGLE CRYSTAL DURING LOADING

摘要

The strain fields near a 100 μm notch in a single crystal of copper have been measured. The notch lies in a { 110} plane and prospective crack growth is in a <100> direction. The surface strains were measured during loading using a microscopic moire method. Data from six load levels are presented for an approx. 2 by 2.5 mm region on one side of the notch tip. These data show that the patchy strain field observed in an iron-silicon single crystal with an identical orientation also occurred in this copper single crystal. Four (8 symmetric) strain sectors form, however, the strain field does not develop in a proportional manner. Initially slip occurs in the second sector and this is visible as discrete slip bands. This deformation leads to the formation of a fan type strain field in the third sector as the overall strain level increases.