Loading rate dependent relaxation under indentation of borophosphate glass

The plasticity of glasses under compressive and shear stresses is governed by 2 main mechanisms: densification and shear flow. The relative contribution of each of these mechanisms depends on the glass structure and its atomic packing density. It was shown that the decrease of loading and hence strain rate contribute to the intensification of both shear flow and densification processes under indentation of phosphate glass [1]. In the present work we have investigated the influence of the loading rate on the relaxation processes during holding under the load and during unloading period

Regularities of the formation of the microstructure of phosphate glasses doped with rare-earth elements

Intensive research into the various types of glassy materials (GMs) is being conducted due to their widespread application in many areas of modern engineering. However, despite the progress made in understanding the internal structure of GMs on the nanometer scale, the problem of the structure of long-range order on the nano/micro/macro scale remains very hypothetical. Therefore, we have studied the nano-microstructure of a large set of GMs belonging to the PhGs-R2O3 system, where R is rare earth metals (Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb) and film/substrate structures (P2O5⋅SiO2/SLG; P2O5⋅SiO2⋅Nd2O3/SLG, SLG is soda-lime-glass). We have shown that regardless of type of GMs, common cluster-icosahedral-fractal regularities take place during the formation of GMs. Close similarity between our results and the images of the literature data makes it possible to express an opinion of the cluster-fractal structure of GMs of different nature for both bulk glasses and film/substrate structures

Prolonged holding and cyclic loading indentation of aluminophosphate glass: kinetics of deformation

The time-dependent mechanical behavior of aluminophosphate glasses (APG) (Li2O–Al2O3–BaO–La2O3–P2O5–RE2O3, RE = Dy, Tb) subjected to dynamic indentation under prolonged holding and cyclic loading conditions in combination with different loading rates is presented in this work. Analysis of the load-displacement (P-h) and displacement-time (h-t) dependences was applied to investigate the deformation peculiarities and kinetics of deformation in these conditions

Micro- and macro-mechanical properties of aluminophosphate glasses depending on their compozition and loading conditions

In this study the deformation peculiarities of aluminophosphate glasses (Li2O-Al2O3-BaO-La2O3-P2O5) doped with Dy, Tb and Fe were investigated at concentated load action (indentation) and uniaxial compression. Dynamic nanoindentation techique with Berkovich indenter were used for hardness (H) and elastic modulus (E) measurements, as well as for the investigation of the kinetics of deformation through the analisys of strain rate during indentation and its influence on the deformation mechanisms

Fracture toughness and hardness at micro- and nanoindentation of phosphate glasses depending on their composition

Two groups of glasses of a basic aluminophosphate (Al2O3–P2O5–Li2O–BaO–La2O3) composition (APG) doped with Dy2O3, Tb2O3 and Fe2O3, and borophosphate (B2O3–P2O5–Li2O–Al2O3–ZnO) composition (BPG) codoped with Dy2O3–Tb2O3, Bi2O3–PbO and CoO were investigated for hardness (H), Young’s modulus (E) and fracture toughness (KIC) and the comparative analysis was carried out. The dynamic nanoindentation and quasistatic microindentation technique within the load range of 0.02–2.0 N were used in this study

Surface morphology and strength behaviour of vitreous films doped by neodymium

The SiO2-P2O5 films demonstrated quite good adhesive behavior. At the same time less cohesion strength ’film-substrate’ was revealed for the composite structure SiO2-P2O5-Nd2O3/SLG. A further research will be directed at the improvement of the adhesive behavior of structure under study