Premium
Effect of pressure and temperature on viscosity of a borosilicate glass
Author(s) -
Ding Linfeng,
Thieme Manuel,
Demouchy Sylvie,
Kunisch Clemens,
Kaus Boris J. P.
Publication year - 2018
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15588
Subject(s) - viscoelasticity , borosilicate glass , materials science , viscosity , thermodynamics , activation energy , atmospheric temperature range , stress (linguistics) , glass transition , composite material , analytical chemistry (journal) , mineralogy , chemistry , physics , polymer , linguistics , philosophy , chromatography
During industrial glass production processes, the actual distribution of stress components in the glass during scribing remains, to date, poorly quantified, and thus continues to be challenging to model numerically. In this work, we experimentally quantified the effect of pressure and temperature on the viscosity of SCHOTT N‐ BK 7 ® glass, by performing in situ deformation experiments at temperatures between 550 and 595°C and confining pressures between 100 and 300 MPa. Experiments were performed at constant displacement rates to produce almost constant strain rates between 9.70 × 10 −6 and 4.98 × 10 −5 s −1 . The resulting net axial stresses range from 81 to 802 MPa, and the finite strains range from 1.4% to 8.9%. The mechanical results show that the SCHOTT N‐ BK 7 ® glass is viscoelastic near the glass transition temperature at 300 MPa of confining pressure. To elucidate the data, we incorporated both 1‐element and 2‐element generalized Maxwell viscoelastic models in an inversion approach, for which we provide MATLAB scrips. Results show that the 2‐element Maxwell model fits the experimental data well. The stress decreases with increasing temperature at 300 MPa and the temperature dependence yields a similar activation energy (601 ± 10 kJ mol −1 or ∆ H / R = 7.2 × 10 4 K) to a previously reported value at 1‐atm (615 kJ mol −1 or ∆ H / R = 7.4 × 10 4 K). The SCHOTT N‐ BK 7 ® glass shows a limited linear increase in viscosity with increasing pressure of ~0.1 log 10 (Pa·s)/100 MPa, which is in agreement with the most recent 2‐internal‐parameter relaxation model (based on experiments).