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.

铁电硫酸三甘氨酸 (TGS) 单晶通过缓慢蒸发技术在 30-40 天内生长。维氏显微硬度研究已在 (001)、(010)、(101)、($\bar{1}$$\bar{1}$1) 和 ($\bar{1}$11) TGS 晶体的面。使用具有铁电相的生长态（001）面和（010）面来研究硬度的温度依赖性。使用五种理论模型（即迈耶定律、海斯-肯德尔定律、弹性/塑性变形 (EPD)、比例样本电阻 (PSR) 和修正的 PSR 模型）描述的压痕尺寸效应 (ISE) 在所有晶面上进行了研究学习。实验结果表明，修改后的 PSR 模型在生成与载荷无关的硬度数据方面更加准确，并且也可以解释 ISE 的起源。