ナノインデンテーション法における材料異方性を考慮した弾性特性評価

抄録

Nanoindentation is a useful tool for measuring regional elastic modulus. However, the elastic moduli of some anisotropic single crystals measured by nanoindentation are often different from theoretical value that is calculated by elastic constants from ultrasonic method. The main cause of the difference is still incompletely understood. One probable reason is a deviation from apparent contact area due to plastic deformation such as pile-up. Therefore, it is effective to evaluate the indentation modulus during fully elastic deformation. In this study, we investigated the cause of the problem above by measuring indentation moduli of some single crystals (4H-SiC, sapphire, quartz, tungsten, CaF₂ and silicon) with a Berkovich and a spherical indenter. The tendency of the comparison between experimental and theoretical indentation moduli is different depending on the measuring materials. To evaluate the indentation modulus independent of the measuring method, it suggests being useful to carry out completely elastic indentation with spherical indenter.