A simple method to evaluate anisotropic plastic properties based on dimensionless function of single spherical indentation – Application to SiC whisker-reinforced aluminum alloy

In this study, an evaluation method for anisotropic plastic properties is proposed using dimensional analysis of single spherical indentation. The method considers a plastically anisotropic material, whose properties are different among orthogonal directions (e.g. longitudinal and transverse direction). In other words, the stress–strain curves along both directions can be simultaneously determined by the present method. When a spherical indenter is impressed against a plane cut along the longitudinal direction (i.e. indentation was conducted along the transverse direction), the impression geometry was found to change depending on the orthogonal axis. That is, the pile-up height in the transverse direction becomes higher than that in the longitudinal one. Using this characteristic and the indentation curve, dimensional functions were established in order to deduce anisotropic plastic properties. Extensive finite element analysis was first carried out to compute the indentation response (indentation curve and impression geometry). Subsequently, dimensionless functions connecting the anisotropic plastic properties to the indentation response were established. The effectiveness of the method was verified by numerical experiments. Finally, an indentation experiment was carried out on an SiC whisker-reinforced aluminum alloy to deduce the anisotropic plastic properties. The estimation results were found to be reliable. The present method is thus useful for determining the plastic properties of various anisotropic materials, such as cold-worked steel, composites and coatings.