Analysis of Indentation Size Effect (ISE) Behavior in Low-Load Vickers Microhardness Testing of (Sm123)$_{\mathbf{1-x}}$(Nd123)$_{\mathbf{x}}$ Superconductor System

Indentation size effect (\textit{ISE}) for (Sm123)$_{1-x}$(Nd123)$_{x}$ superconducting samples which were fabricated by the solid state reaction technique for values of x$=$0.00, 0.05, 0.10, 0.20, and 0.30 was investigated by analyzing the theoretical models. When the experimental data of a number of single crystals which have the different crystal structure and different chemical bonding inside the polycrystallined samples were analyzed with the \textit{ISE} models, the sample encountering with resistance and elastic deformation was observed as well as plastic deformation. The microhardness values on different surfaces of materials were calculated by using Meyer Law, \textit{PSR} model, MPSR model, \textit{EDP} (Elastic / Plastic Deformation model) model and the Hays-Kendall (\textit{HK}) approach. The results showed that the Hays- Kendall approach was determined as the most successful model. Furthermore, XRD and SEM measurements were analyzed for superconducting properties of (Sm123)$_{1-x}$(Nd123)$_{x}$ superconductor system. The results showed that while Nd123 concentration is increasing, microhardness values at the minimum load and averaged plateau region of load.