Dynamic Vickers indentation of brittle materials

Static and dynamic Vickers indentations were performed on brittle materials to investigate the rate effects in hardness, induced crack morphologies, a nd fracture toughness. The dynamic indentations were performed on a hardnes s tester, which utilizes elastic stress wave propagation phenomena in a sle nder rod that can deliver indentation loads of 100 mu s durations. Under dy namic indentations, an increase in hardness was observed in all the brittle materials compared to their static hardness measurements. Analysis of the evolved crack morphology revealed an increase in fracture toughness for zir conia ceramics and a decrease in fracture toughness for pyrex glass under d ynamic indentations. The implications of the rate dependence of hardness an d fracture toughness on material removal mechanisms are discussed. (C) 2000 Elsevier Science S.A. All rights reserved.