Surface damage resistance and yielding of chemically strengthened silicate glasses: From normal indentation to scratch loading |
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| Authors: | Gohar Sani Rene Limbach Jan Dellith İlkay Sökmen Lothar Wondraczek |
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| Affiliation: | 1. Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Jena, Germany;2. Leibniz Institute of Photonic Technology, Jena, Germany;3. Sisecam Science and Technology Center, Cumhuriyet Mah, Gebze, Kocaeli, Turkey |
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| Abstract: | We report on surface elasticity, plastic deformation and crack initiation of chemically strengthened soda-lime silicate and sodium aluminosilicate glasses during lateral indentation and scratch testing. Instrumented indentation using a normal indenter set-up corroborated previous findings on the effects of chemical strengthening on surface Young's modulus, hardness, and indentation cracking. Using lateral indentation in the elastic-plastic regime, we find a pronounced increase in the scratch hardness as a result of chemical strengthening, manifest in higher work of deformation required for creating the scratch groove. Thereby, the glass composition is found to play a stronger role than the absolute magnitude of surface compressive stress. Using a blunt conical stylus for instrumented scratch testing reveals three distinct modes of scratch-induced surface fracture, which occur during scratching or after unloading. Occasional micro-cracking caused by pre-existing surface flaws at low scratching load can be completely suppressed through chemical strengthening. The intrinsic defect resistance to microcracking is reduced as a result of ion stuffing, depending on the initial glass composition, whereas the resistance to abrasive yielding is enhanced by several hundred MPa. |
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| Keywords: | abrasive wear chemical strengthening crack resistance glass hardness indentation mechanical properties scratching |
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