An experimental investigation of the scratch behaviour of polymers: 1. Influence of rate-dependent bulk mechanical properties

The scratch behaviour displayed by a series of polymers in constant penetration depth scratch tests conducted by a microscratch tester was examined in relation to their intrinsic rate-dependent mechanical properties. Scratch hardness, which is considered as a measure of the scratch performance, was assessed by using a recently proposed scratch model. The adequacy of the model to explain deformation recovery and pile-up characteristics of the material in the scratch test was questioned by comparing the predictions of the model with residual profile measurements. The study demonstrated that the scratch phenomenon is dominated by the yield stress of the material. Besides, scratch hardness was found to be independent of the loading conditions. Indentation hardness and scratch hardness are comparable if the testing conditions are similar.