Kinetic model for phase transformation of noncrystalline solids: Application to permanent densification of SiO2 glass

2021 ◽  
Vol 103 (14) ◽  
Author(s):  
Daisuke Wakabayashi ◽  
Nobumasa Funamori ◽  
Tomoko Sato
Keyword(s):  
Phase Transformation ◽  
Kinetic Model ◽  
Sio2 Glass ◽  
Permanent Densification

scholarly journals Macroscopic and microscopic strain of SiO2 glass under uniaxial compression

2014 ◽  
Vol 70 (a1) ◽  
pp. C1333-C1333
Author(s):  
Nobumasa Funamori ◽  
Daisuke Wakabayashi ◽  
Tomoko Sato ◽  
Takehiko Yagi
Keyword(s):  
Plastic Deformation ◽  
Network Structure ◽  
High Pressures ◽  
Microscope Observation ◽  
Macroscopic Strain ◽  
X Ray Diffraction ◽  
Sio2 Glass ◽  
X Ray ◽  
Intermediate Range ◽  
Permanent Densification

Although SiO2 glass is brittle due to its covalency and the lack of dislocation movement seen in crystals, it can deform without fracturing when compressed to high pressures. The phenomenon may be attributable to the well-known permanent densification by the reconstruction of the network structure consisting of SiO4 tetrahedra. To explore so-called plastic deformation without permanent densification, we measured the change in size (macroscopic strain) of uniaxially-compressed disk-shaped SiO2 glass by an optical microscope [1]. Also, to understand the anisotropy in structure (microscopic strain), we measured the azimuth-angle dependence of the position of the first sharp diffraction peak (FSDP) of uniaxially-compressed SiO2 glass with a radial X-ray diffraction technique [2]. In the microscope observation, the glass was found to deform largely without fracturing up to at least 20 GPa from 6-8 GPa, where uniaxial conditions were achieved. In the X-ray diffraction observation, a large anisotropy was found in the FSDP which corresponds to the intermediate-range network structure of the glass. The recovered glass was examined by the radial X-ray diffraction up to a high-Q range and was found to remain largely anisotropic (equivalent to about 2 GPa in differential stress) in the intermediate-range network structure and not to remain anisotropic in the short-range SiO4 tetrahedral structure. It seems intuitive that the residual anisotropy is due to the anisotropic reconstruction of the network structure during permanent densification. However, the macroscopic strain measured in the microscope observation was an order of magnitude larger than the microscopic strain in the X-ray diffraction observation, and therefore it cannot be explained solely by the anisotropic permanent densification. The permanent densification may also enhance the reconstruction of the network structure and therefore plastic deformation.

scholarly journals Overview of Phase-Change Electrical Probe Memory

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 772 ◽  
Author(s):  
Lei Wang ◽  
Wang Ren ◽  
Jing Wen ◽  
Bangshu Xiong
Keyword(s):  
Phase Transformation ◽  
Kinetic Model ◽  
Phase Change ◽  
State Of The Art ◽  
The State ◽  
Design Rule ◽  
Next Generation ◽  
Future Prospects ◽  
Storage Devices ◽  
Electrical Probe

Phase-change electrical probe memory has recently attained considerable attention owing to its profound potential for next-generation mass and archival storage devices. To encourage more talented researchers to enter this field and thereby advance this technology, this paper first introduces approaches to induce the phase transformation of chalcogenide alloy by probe tip, considered as the root of phase-change electrical probe memory. Subsequently the design rule of an optimized architecture of phase-change electrical probe memory is proposed based on a previously developed electrothermal and phase kinetic model, followed by a summary of the state-of-the-art phase-change electrical probe memory and an outlook for its future prospects.

Phase-Transformation Kinetics of TiO2 in TiO2/(O′+β′)-Sialon Multi-Phase Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 2318-2321
Author(s):  
Jian Yang ◽  
Xiang Xin Xue ◽  
Li Mei Pan ◽  
Mei Wang ◽  
Tai Qiu
Keyword(s):  
Phase Transformation ◽  
Kinetic Model ◽  
Raw Materials ◽  
Transformation Process ◽  
Transformation Kinetic ◽  
Order Kinetic ◽  
Weight Percentage ◽  
Tio2 Anatase ◽  
Additive Content ◽  
Kinetics Of

TiO2/(O′+β′)-Sialon multiphase ceramics with different phase composition of TiO2 were prepared by pressureless sintering under high-purity N2 atmosphere with (O′+β′)-Sialon powder and nano TiO2 (anatase) powder as raw materials, Yb2O3 or Tb2O3 as additive. For each sample, the weight percentage of anatase in TiO2 was calculated from XRD data and the kinetics of anatase-rutile transformation was investigated, wherein the emphasis was placed on the influence of Yb2O3 and Tb2O3. The results indicate that the added Tb2O3 and Yb2O3 serve the significant function of inhibition and promotion on the phase transformation, and the effects are enhanced and attenuated with increasing additive content, respectively. For the sample without additive, the transformation process follows apparent first-order kinetic model. The addition of Yb2O3 or Tb2O3 results in completely different transformation kinetic law. For the samples with Yb2O3 added, the transformation is an apparent second-order reaction, whereas a unique kinetic model, CA=kt1/2+C, is valid for the samples containing Tb2O3. In the two cases, the effect of the additive content on the transformation can be perfectly reflected by the apparent rate constant.

scholarly journals Kinetic Model of ^|^gamma; to ^|^alpha; Phase Transformation at Grain Boundaries in B-Bearing Low Alloy Steel

2012 ◽  
Vol 98 (9) ◽  
pp. 482-490 ◽  
Author(s):  
Suguru Yoshida ◽  
Kohsaku Ushioda ◽  
Yoshio R. Abe ◽  
John ^|^Aring;gren
Keyword(s):  
Phase Transformation ◽  
Kinetic Model ◽  
Grain Boundaries ◽  
Alloy Steel ◽  
Alpha Phase ◽  
Low Alloy Steel

scholarly journals Microstructure Study of Phase Transformation of Quartz in Potassium Silicate Glass at 900 °C and 1000 °C

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1481
Author(s):  
Wenbo Li ◽  
Chenghao Xu ◽  
Ameng Xie ◽  
Ken Chen ◽  
Yingfei Yang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Interfacial Reaction ◽  
Silicate Glass ◽  
Quartz Glass ◽  
Firing Temperature ◽  
Heterogeneous Nucleation ◽  
Potassium Silicate ◽  
Transformation Rate ◽  
Sio2 Glass ◽  
Glass Interface

Interfacial reaction between quartz and potassium silicate glass was studied at both 900 °C and 1000 °C. The results showed that no phase transformation was observed for the pure quartz at 900 °C or 1000 °C. Instead, for quartz particles in K2O-SiO2 glass, the transformation from quartz to cristobalite occurred at the quartz/glass interface at first, and then the cristobalite crystals transformed into tridymite. The tridymite formed at the interface between particles and glass became the site of heterogeneous nucleation, which induces plenty of tridymite precipitation in potassium silicate glass. The influential mechanism of firing temperature and size of quartz particles on transformation rate was discussed.

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