Densification contribution as a function of strain rate under indentation of terbium-doped aluminophosphate glass
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In this work, the strain rate effect on the deformation processes under Berkovich indentation of Tb-doped aluminophosphate glass has been investigated. It is shown that both densification and shear flow, adopted as main mechanisms of plastic deformation for oxide glasses, are strain rate sensitive. Moreover, the shear flow is assumed to be responsible for the strain rate sensitivity of densification. The densification contribution to the total plastic deformation is found to be greater for lower strain rate, and the same tendency is observed for the plastic flow. This, in turn, leads to the influence of the strain rate on the hardness values, manifesting as a softening of the glassy matrix with the decrease of strain rate caused by more intensive development of the densification and shear flow. The decrease of hardness with load increase is attributed to the involving and increasing contribution of the shear flow and fracture to the total deformation process.
KeywordsShear Flow Strain Rate Sensitivity Silica Glass Phosphate Glass Indentation Size Effect
The authors would like to acknowledge T. Braniste, National Center for Materials Study and Testing, Technical University of Moldova, for AFM measurements. This work was supported by SCSTD Academy of Sciences of Moldova—project No. 15.817.02.06A and Bilateral Collaborative Program between ASM and UEFISCDI-Romania—project No. 13.820.05.20/RoF, contract 20/RoF (Moldova Republic), and 695/2012 (Romania), as well as contract 186/2012—Partnership Program (UEFISCDI-Romania) and M-ERA.NET 7-081/2013 MAGPHOGLAS project.
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