The transition between ductile and slow-crack-growth failure in polyethylene

In the neighbourhood of room temperature, linear polyethylene will exhibit two types of long-time failure under a constant stress: (a) ductile failure, which is produced by a creep process, and (b) brittle fracture, which is produced by slow crack growth. The kinetics of each failure process have been quantitatively represented based on experimental data. The transition time from one failure mechanism to the other has been calculated in terms of the material parameters relevant to each failure mechanism and the defect responsible for crack growth.