Shear deformation and fracture behaviour of polycarbonate–acrylonitrile/butadiene/styrene blend at high strain rates

Abstract

The purpose of the present research was to study systematically the shear deformation and fracture behaviour of a polycarbonate–acrylonitrile/ butadiene/styrene (PC–ABS) blend subjected to high shear strain at high strain rate, using a torsional, split Hopkinson bar. Thin walled tube specimens were deformed at room temperature under strain rates ranging from 10² to 5 × 10³ s^-1. The effects of strain rate on shear flow response, strain rate sensitivity, thermal activation volume, and shear modulus were evaluated. Damage initiation, propagation, and fracture mechanisms were studied by scanning electron microscopy. Correlations between dynamic flow response and observed fracture features are characterised and discussed in terms of loading conditions. The data indicate that the dynamic shear response of the PC–ABS blend is greatly affected by applied strain rate. An increase in shear stress and shear modulus with strain rate was observed. Fracture strains decrease with increased loading rate. Tearing and shear fracture are the major fracture mechanisms and depend quite strongly on the strain rate.