Nanoindentation characterisation of HfC-based composites

Two hot-pressed HfC-based composites with 10 and 20 vol% of MoSi2 were characterised by nanoindentation tests. The hardness and the Young's modulus of the constituent phases were measured at low peak loads. They resulted independent on the considered composite. With higher peak loads, the same properties were measured and attributed to the composites. In this peak load range, the Young's modulus and hardness decreased by increasing the peak load. Inserting the values of the constituent phases in simple composites models, the upper and lower bounds for the composites properties were calculated and compared to the experimental results.