Polymer, Vol.41, No.16, 6285-6293, 2000
Simple shear plastic deformation behavior of polycarbonate plate II. Mechanical property characterization
It has been demonstrated in Part I of this research that the high degree of plastic deformation caused by the equal channel angular extrusion (ECAE) process leads to a nearly uniform molecular orientation across the extruded polycarbonate (PC) plate. In this paper, the effectiveness of the ECAE process in altering the mechanical property of PC is investigated. Significant improvements in flexural modulus and fracture toughness are observed, and are found to be closely related to the ECAE-induced molecular orientation. Microscopy observations of the fracture process show that the crack propagation direction is controlled both by the ECAE-induced molecular orientation direction and by the maximum principal stress direction, which results in the formation of hackles. Potential advantages of ECAE for fabricating polymer parts are addressed.