Universal hardness and elastic recovery in Vickers nanoindentation of copper phosphate and silicate glasses

Loading Rate Effect on Nanohardness of Soda-Lime-Silica Glass

“…It was suggested further [8] that the shear plane generally avoids the covalently bonded siloxane polymeric anions by finding a path through the ionically bonded modifier-rich interfaces between the anions. Further, Kurkjian et al reported that the deformation of soda-lime-silica glass was caused mainly by shear flow at room temperature, e.g., 300 K. [11] Miura et al [12] showed genuine shear flow induced plastic deformation underneath Vicker's nanoindentation in a soda-limesilica glass. It was suggested that the large amount of modifiers (Na 2 O and CaO) included in the soda-limesilica glass led to the formation of nonbridging oxygens and weaker bonds such as Na + -O À .…”

“…[5][6][7][8]11,12] It is plausible then to imagine that there can be many nearby locations where slip band formations on an atomistic scale could be favorable. Of course, the strain would radically decrease at points far away from such positions of local maxima.…”

“…[1][2][3][4] Glass shows irreversible deformation on sharp contact loading, which can be classified into one of the two following groups: plastic (or shear) flow induced shear band formation or densification. [5][6][7][8][9][10][11][12][13] There is much evidence of anomalous glasses such as fused silica, [5,9,11,12] silicate glasses, [8,13] etc. showing densification of material beneath the indenter.…”

“…showing densification of material beneath the indenter. However, in the case of usual glasses such as the soda-lime-silica glass, most of the researchers observed shear flow [5][6][7][8][10][11][12] induced slip lines/shear band formation beneath the indenter in macro-, micro-, and nanoindentation studies.…”

XRD and Microhardness Studies of Ni2+ and W6+ Transition Metal Ions Doped with Tellurite Barium Borate Glasses

“…It is known that some extent of deformation during loading is recovered duringunloading, i.e., elastic recovery.Since it is expected that the degree ofelastic recovery depends on glass systems and glasscompositions, the hardness evaluated from a residualsurface impression after unloading is insufficient for anin-depth understanding of deformation behaviors inglass. In this point of view, it is also important to evaluate the hardness during loading, i.e., the so-called'universal hardness' [7] .In the past decades, there has been a considerable increase in the use of indentation techniques for determining mechanical properties of solids [8] . Generally, the apparent hardness of the materials varies with applied load.…”