Densification contribution as a function of strain rate under indentation of terbium-doped aluminophosphate glass

Shikimaka, O.; Grabco, D.; Sava, Bogdan Alexandru; Elisa, M.; Boroica, Lucica; Harea, Evghenii; Pyrtsac, Constantin; Prisacaru, A.; Barbos, Zinaida

doi:10.1007/s10853-015-9460-8

Cited by 13 publications

(5 citation statements)

References 40 publications

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“…In this context, it appears that ZIF glasses display a relatively typical behavior. Yet, the relatively low strain-rate sensitivity determined here for a g ZIF-62 compared to other glasses is in line with the trend for highly cross-linked networks and a small packing density of approximately 0.6 (Supporting Information 1), which deform mainly through compaction of the free volume. , This relationship can be understood qualitatively from the fact that purely displacive densification requires less thermal activation than shear flow, which involves the breaking and re-forming of bonds. , Further support for a densification-dominated plasticity stems from nanoindentation experiments that showed practically no pile-up …”

Section: Resultssupporting

confidence: 81%

Plasticity of Metal–Organic Framework Glasses

et al. 2021

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Metal−organic framework (MOF) glasses provide new perspectives on many material properties due to their unique chemical and structural nature. Their mechanical properties are of particular interest because glasses are inherently brittle, which limits their applications as structural materials. Here we perform strainrate-dependent uniaxial micropillar compression experiments on a g ZIF-62, a g ZIF-UC-5, and a g TIF-4, a series of MOF glasses with different substituting linker molecules, and find that these glasses show substantial plasticity, at least on the micrometer scale. At a quasi-static strain rate of 0.001 s −1 , the micropillars yielded at approximately 0.32 GPa and subsequently deformed plastically up to 35% strain, irrespective of the type of substituting linker. With increasing strain rate, the yield strength of a g ZIF-62 evolved with the strain-rate sensitivity m = 0.024 to reach a yield strength of 0.44 GPa at a strain rate of 510 s −1 . On the basis of this relatively low strain-rate sensitivity and the absence of serrated flow, we conclude that structural densification is the predominant mechanism that accommodates such extensive plasticity.

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Section: Resultssupporting

confidence: 81%

Plasticity of Metal–Organic Framework Glasses

et al. 2021

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“…Performing post indent annealing experiments, Shikimaka et al have shown that densification contribution to plastic flow is larger for small strain rates. At small strain rates, the material behaves softer and rearrangement processes in the material become easier (Shikimaka et al, 2016). That is why lower strain rates result in lower hardness values, which agrees very well with our results (Figure 3).…”

Section: The Effect Of Strain Rate On the Deformation Mechanismsupporting

confidence: 92%

“…In general, both processes, densification and shear flow are sensitive toward changes in strain rate (Shikimaka et al, 2016); the contribution of each, however, depends on composition, atomic packing density, and network connectivity (Yoshida et al, 2005;Limbach et al, 2014;Möncke et al, 2016). Shikimaka et al (2016) concluded densification to be triggered by shear and pressure.…”

Section: The Effect Of Strain Rate On the Deformation Mechanismmentioning

confidence: 99%

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Influence of Cooling Rate on Cracking and Plastic Deformation during Impact and Indentation of Borosilicate Glasses

et al. 2017

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The influence of a changing glass topology on local mechanical properties was studied in a multitechnique nanomechanical approach. The glass response against sharp contacts can result in structural densification, plastic flow, or crack initiation. By using instrumented indentation testing, the mechanical response was studied in different strain rate regimes for a sodium borosilicate glass (NBS) exhibiting altering structures due to varying processing conditions. Comparison with data from former studies and with literature data on other glass structures helped to elucidate the role of the borate and silicate subnetworks and to understand the overall mechanical properties of the mixed glass systems. A peculiarity of some of the NBS glasses tested in this study is the fact that the connectivity of the borate and silicate entities depends on the sample's thermal history. Although the influence on macroscopic material properties such as E and H is minor, the onset of cracking indeed is influenced by those structural changes within the glass. Rapidly quenched glass shows an improved crack resistance, which is even more pronounced at high strain rates. Studies on various processing conditions further indicate that this transition is closely related to the cooling rate around Tg. The strain rate dependence of cracking is discussed in terms of the occurrence of shear deformation and densification.

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“…Increased values of hardness, Young’s modulus and fracture toughness of Bi, Pb-doped borophosphate glasses were reported [ 8 ] in comparison with the un-doped phosphate glasses [ 9 ] and rare-earth-doped phosphate glasses [ 10 ], due to the mixed glass former role of P 2 O 5 and B 2 O 3 components, which contribute to structural strengthening. The deformation of phosphate glasses under different load (strain) rates depends on the evolution of four mechanisms, namely, elastic deformation, densification, shear flow and fracture [ 11 ]. For reduced indentation loads, the first two mechanisms are prevalent, whereas shear flow and fracture are predominant for high-applied loads.…”

Section: Introductionmentioning

confidence: 99%

Investigations Regarding the Addition of ZnO and Li2O-TiO2 to Phosphate-Tellurite Glasses: Structural, Chemical, and Mechanical Properties

Elisa

Iordache

et al. 2022

Materials

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Phosphate and tellurite glasses can be used in optics, optoelectronics, magneto-optics, and nuclear and medical fields. Two series of phosphate-tellurite glasses, (50-x)ZnO-10Al2O3-40P2O5-xTeO2 and (40-x)Li2O-10Al2O3-5TiO2-45P2O5-xTeO2 (x = 5, 10), were synthesized by a non-conventional wet-route, and the mechanical properties as key performance measures for their application in optoelectronics were investigated. X-ray Diffraction (XRD) measurements revealed the vitreous nature of the investigated materials. Instrumented indentation tests allowed the calculation of hardness (H) and Young’s modulus (E) using the Oliver and Pharr model. The influence of increasing the TeO2 content, as well as the substitution of ZnO by Li2O-TiO2, on the variation of hardness, Young’s modulus, penetration depth (PD), and fracture toughness (FT) was evaluated in both series. As a general trend, there is a decrease in the hardness and Young’s modulus with increasing penetration depth. The addition of Li2O and TiO2 instead of ZnO leads to improved hardness and elastic modulus values. Regarding the H/E ratio, it was found that the samples with lower TeO2 content should be significantly more crack-resistant compared to the higher TeO2 content samples. The H3/E2 ratio, being lower than 0.01, revealed a poor resistance of these glasses to plastic deformation. At the same time, a decrease of the fracture toughness with increasing TeO2 content was noticed for each glass series. Based on dilatometry measurements, the thermal expansion coefficient as well as the characteristic temperatures of the glasses were measured. Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray analysis (FESEM-EDX) revealed a uniform distribution of the elements in the bulk samples. The mechanical properties of these vitreous materials are important in relation to their application as magneto-optical Faraday rotators in laser cavities.

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Densification contribution as a function of strain rate under indentation of terbium-doped aluminophosphate glass

Cited by 13 publications

References 40 publications

Plasticity of Metal–Organic Framework Glasses

Plasticity of Metal–Organic Framework Glasses

Influence of Cooling Rate on Cracking and Plastic Deformation during Impact and Indentation of Borosilicate Glasses

Investigations Regarding the Addition of ZnO and Li2O-TiO2 to Phosphate-Tellurite Glasses: Structural, Chemical, and Mechanical Properties

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