| Abstract: | A study of the kinetics, failure mechanism, and fracture surfaces of PMMA/methanol crazes has been made on notched circular bar specimens subjected to constant tensile loads. Failures were by void growth and coalescence inside the craze away from the notch tip and near to the specimen center. Two distinct features of void coalescence were observed; the first a cluster of very small voids (each of the order of 3.4 × 103 Å) and the second, separate larger voids which usually caused final failure. An analysis of craze growth, based on fracture mechanics concepts in conjunction with simple flow analysis, suggests that the growth is controlled mainly by the ability of the environment to flow through the voided structure of the craze. Good agreement has been obtained between predicted behavior and experimental data. |
