Vickers microindentation hardness studies of β-Sn single crystals

The Vickers microindentation hardness anisotropy profile and load dependence of apparent hardness of white tin (β-Sn) single crystals having different growth directions were investigated. Indentation experiments were carried out on the (001) crystallographic plane at indentation test loads ranging from 10 to 50 mN. Examinations reveal that the degree of the hardness anisotropy decreases with increasing indentation test load. Also, the materials examined exhibit significant peak load dependence (i.e., indentation size effect (ISE)). The traditional Meyerʹs law, proportional specimen resistance (PSR) model and modified PSR (MPSR) model, were used to analyze the load dependence of the hardness. While Meyerʹs law can not provide any useful information about the observed ISE, the load-independent hardness (i.e., HPSR and HMPSR) values can be estimated for different crystallographic directions, using the PSR and MPSR models. Briefly, for microindentation hardness determinations of β-Sn single crystals, the MPSR model is found to be more effective than the PSR model.