Temperature Dependence of the Elastic Moduli and Internal Friction of Silica and Glass

Abstract

Articles you may be interested inA simple model to predict the temperature dependence of elastic moduli of bulk metallic glassesThe dynamic Young's moduli and the internal friction of fused quartz, Pyrex glass, and soft glass rods were measured at a frequency of 37 kilocycles, in longitudinal vibration, within the temperature range -170° to 1000°C. The moduli of Pyrex and quartz increased with rising temperature, up to the softening point of the glass, while that of soft glass decreased. All three moduli were approximately linear with respect to the temperature over most of the measurement interval. Internal friction maxima were noted at high temperatures, while at the lowest measurement temperatures a significant increase in background damping occurred. A brief recapitulation of existing theory is given and employed to interpret the internal friction data. It is suggested that, in microscopically inhomogeneous media, the diffusion measurement by internal friction methods is not equivalent to the determination by other teclmiques.

Hot nanoindentation in inert environments

“…The present data, which align well with the results of Ref. 33 , also agree with acoustic measurements of the modulus of fused silica [60][61][62][63] compiled in Ref. 33 .…”

Effect of heat treatment on mechanical dissipation in Ta 2 O 5 coatings

“…The Young's moduli of silicon and Ta 2 O 5 were taken to be 166 GPa [41] and (140 ± 15) GPa [42] respectively. Assuming that the temperature dependence of the Young's modulus of Ta 2 O 5 is typical of other amorphous oxides [43], then its effect on the calculation over the temperature range studied here is negligible. Figure 3 shows the calculated mechanical dissipation of the Ta 2 O 5 film heat treated at 300…”

Examining the Validity of the Phonon Gas Model in Amorphous Materials

“…Furthermore, one would also expect that any temperature dependence associated with the velocities of modes in a given material must still exhibit similar temperature dependence to the speed of sound or modulus, which generally do not show strong temperature dependence for amorphous materials27. For example, in the case of amorphous silicon (a-Si)28 and a-SiO 2 2930, the change in modulus with temperature is less than 10% for both a-Si between 200–800 K and a-SiO 2 between 100–1200 K. Consequently, the sound velocity, which is proportional to the square root of the modulus, then only changes by less than 4% over these respective temperature ranges. Hence an important, yet physically well-reasoned assumption herein is that phonon velocities (v g ( n )), whether defined or ill defined, must still exhibit negligible temperature dependence (e.g., as compared to the heat capacity and relaxation times.…”