FATIGUE CRACK GROWTH BEHAVIOR OF PC AND PC/ABS

Abstract

The fatigue crack growth behavior of polycarbonate(PC) and the alloy of PC and acrylonitrile-butadiene-styrene(PC/ABS) is experimentally investigated in this paper.An improved compliance method is employed to measure the fatigue crack length of these polymers.The fatigue crack growth law from low(10-6 mm/cycle) to high(10-3 mm/cycle) growth rate is obtained for polymer PC/ABS,which could be fairly represented in terms of stress intensity factor through the well-known Paris law,i.e.da/dN=9.5587×10-5(ΔK)2.88381.The fatigue crack growth rate of PC is about two times higher than that of PC/ABS.Variation of the crack growth rate in the lower crack growth rate region is larger than that in the higher crack growth rate region.For PC/ABS,dimple features are observed on the fatigue fracture surfaces of PC/ABS alloy for the crack growth rate region tested in the experiment,which are coarser for larger crack growth rate,smoother for smaller crack growth rate.The fatigue crack surfaces for PC are smoother than that for PC/ABS,and discontinuous crack growth bands are observed.