Mechanical properties of Si3N4/SiC nanocomposites studied by instrumented indentation with spheres

Contact deformation behaviour and mechanical properties of two Si3N4/SiC nanocomposites with different SiC content were investigated by nanoindentation with spherical diamond indenter (radius 5 μm) at low loads (1–300 mN) using depth sensing techniques. From the measurement of the tip displacement depending on the load and the tip geometry, the total and the remnant depth of penetration were found. Based on the results we were able to study elastic, yield and plastic behaviour. Using the method of partial unloading, the contact stress-strain curves, hardness, and modulus of elasticity were explored. The results were compared to the values obtained by the same method for the reference Si3N4 material.