Indentation size effect (ISE) and R-curve behaviour of Li₂O–SiO₂ and Li₂O–2SiO₂ glass ceramics are investigated using micro-indentation and indentation-strength (IS) techniques, respectively. Vickers micro-indentations were applied on both materials at the load of 0.10–19.6 N to determine the load influence on the measured hardness. For the IS-measured fracture toughness, the load ranged from 1.96 to 19.6 N. The hardness decreased with increasing load by 20% and 18% on Li₂O–SiO₂ and Li₂O–2SiO₂ glass ceramics, respectively, indicating the ISE behaviour on both materials. The fracture toughness increased with the load by 27% and 59% on Li₂O–SiO₂ and Li₂O–2SiO₂ glass ceramics, respectively, signifying the R-curve behaviour. The ISE behaviour of both materials was analysed using the Meyer's, Hays–Kendall (HK), proportional specimen resistance (PSR), Nix–Gao (NG), modified PSR (MPSR) and elastic plastic deformation (EPD) models while the R-curve behaviour was analysed by the fractional power law. The Meyer's index of both materials was less than 2, strongly confirming the ISE existence. The HK, PSR and NG models were only suitable to determine intrinsic Vickers hardness for Li₂O–2SiO₂ glass ceramic while the MPSR and EPD models were successful for both materials. The fractional power law gave higher R-curve steepness for Li₂O–2SiO₂ than Li₂O–SiO₂ glass ceramics. Also, material and brittleness indices predicted, respectively, higher quasi-plasticity and better machinability for Li₂O–2SiO₂ than Li₂O–SiO₂ glass ceramics indicating superior performance in the former to the latter. Finally, this study presents a new significant insight into the micro-mechanisms of fracture tolerance behaviour of these glass ceramics which is critical to their functional performance as structural ceramics.

分别使用微压痕和压痕强度 (IS) 技术研究了 Li ₂ O-SiO ₂和 Li ₂ O-2SiO ₂玻璃陶瓷的压痕尺寸效应 (ISE) 和 R 曲线行为。以 0.10-19.6 N 的载荷在两种材料上施加维氏微压痕，以确定载荷对测量硬度的影响。对于 IS 测量的断裂韧性，载荷范围为 1.96 至 19.6 N。Li ₂ O-SiO ₂和 Li ₂ O-2SiO ₂的硬度随载荷增加 20% 和 18% 降低玻璃陶瓷，分别表明两种材料的 ISE 行为。Li ₂ O-SiO ₂和Li ₂ O-2SiO ₂玻璃陶瓷的断裂韧性随载荷分别增加27%和59% ，表明了R曲线行为。使用 Meyer's、Hays-Kendall (HK)、比例试样电阻 (PSR)、Nix-Gao (NG)、改进的 PSR (MPSR) 和弹性塑性变形 (EPD) 模型分析了两种材料的 ISE 行为，而 R-曲线行为通过分数幂律进行分析。两种材料的迈耶指数均小于 2，有力地证实了 ISE 的存在。HK、PSR 和 NG 模型仅适用于确定 Li ₂ O–2SiO _{2 的}固有维氏硬度玻璃陶瓷，而 MPSR 和 EPD 模型在这两种材料上都取得了成功。分数幂律给出了比 Li ₂ O-SiO ₂玻璃陶瓷更高的 Li ₂ O-2SiO _{2 的}R 曲线陡度。此外，材料和脆性指数分别预测 Li ₂ O-2SiO ₂比 Li ₂ O-SiO ₂玻璃陶瓷具有更高的准塑性和更好的可加工性，表明前者的性能优于后者。最后，这项研究对这些玻璃陶瓷的断裂耐受行为的微观机制提出了新的重要见解，这对其作为结构陶瓷的功能性能至关重要。