Small Punch Testing Method for the Development of Functionally Gradient Materials

This paper discusses the use of a small punch (SP) testing method to determine the elastic modulus and fracture strength of the material. Numerical analyses using the FEM were carried out to calibrate a SP specimen. Three loading modes were analysed to examine the punch tip effect on the deformation and fracture behaviour. Several ceramics and ceramics/metal composites were tested using the SP method, and their mechanical properties were determined using the results of FEM analyses. It is shown that the SP method provides a reliable means for measuring the elastic modulus. Furthermore, it is demonstrated that the fracture strength determined by the SP method shows a good correlation with the bending strength obtained from the three-point bend specimen which is commonly used for the determination of the fracture strength of ceramics.