Observation of instabilities during plastic deformation by in-situ SEM indentation experiments

The plastic deformation behavior of materials was observed from in-situ scanning electron microscopy (SEM). Indentation in Viterloy-105 with a nominal composition of Zr52.5Cu17.9Ni14.6Al 10Ti 5, which was produced by copper mold casting of an arc-melted pre-alloy was performed. Indentation hardness and modulus were calculated from the load displacement curves measured with the Berkovich tip according to the method presented by Oliver and Pharr. A partial correlation between displacement bursts in the load-displacement curve and shear band activity at the specimen surface was found. It was also found that a shear band forms at the same site where the material has already been sheared.