Narrow Results

Ferroelectric triglycine sulphate (TGS) single crystals were grown by slow evaporation technique over a period of 30–40 days. The Vickers microhardness studies have been carried out on (001), (010), (101), ($\bar{1}$$\bar{1}$1) and ($\bar{1}$11) faces of the TGS crystal. The as-grown (001) face and (010) face with the ferroelectric phase were used to study the temperature dependence of hardness. The indentation size effect (ISE) described using the five theoretical models viz., Meyer’s law, Hays–Kendall, elastic/plastic deformation (EPD), proportional specimen resistance (PSR) and modified PSR model has been investigated on all the crystal faces under study. The experimental results show that the modified PSR model is more accurate at generating load-independent hardness data and also for explaining the origin of ISE.

In order to accurately define the nanomechanical performance parameters of single crystal gallium oxide, the microscopic deformation mechanism during processing is analyzed. On the G200 nanoindenter, the Berkovich indenter made of diamond was used to perform nanoindentation experiments on single crystal gallium oxide (100) and (010) crystal planes by using a quasi-static method to set the load. According to the power law relationship and Nix-Gao model proposed by Manika, the relationship between the hardness of the two crystal faces of single crystal gallium oxide and the depth of indentation is fitted, and the single crystal gallium oxide (100) and (010) crystal faces without considering the size influence factor. The hardness is 8.238GPa and 9.824GPa, the micro feature length is 101.196nm and 88.033nm, and the size influence factor is 0.1725 and 0.1706, respectively. The size influencing factors of the two crystal planes are between common metal materials and semiconductor materials. Compared with the (010) crystal plane, the (100) plane exhibits a larger elastic modulus and lower hardness. (100) The indentation size effect of the crystal plane is more obvious.