Kinetics of the B1-B2 phase transition in KCl under rapid compression
- Carnegie Inst. of Washington, Argonne, IL (United States)
Kinetics of the B1-B2 phase transition in KCl has been investigated under various compression rates (0.03–13.5 GPa/s) in a dynamic diamond anvil cell using time-resolved x-ray diffraction and fast imaging. Our experimental data show that the volume fraction across the transition generally gives sigmoidal curves as a function of pressure during rapid compression. Based upon classical nucleation and growth theories (Johnson-Mehl-Avrami-Kolmogorov theories), we propose a model that is applicable for studying kinetics for the compression rates studied. The fit of the experimental volume fraction as a function of pressure provides information on effective activation energy and average activation volume at a given compression rate. The resulting parameters are successfully used for interpreting several experimental observables that are compression-rate dependent, such as the transition time, grain size, and over-pressurization. The effective activation energy (Qeff) is found to decrease linearly with the logarithm of compression rate. When Qeff is applied to the Arrhenius equation, this relationship can be used to interpret the experimentally observed linear relationship between the logarithm of the transition time and logarithm of the compression rates. The decrease of Qeff with increasing compression rate results in the decrease of the nucleation rate, which is qualitatively in agreement with the observed change of the grain size with compression rate. In conclusion, the observed over-pressurization is also well explained by the model when an exponential relationship between the average activation volume and the compression rate is assumed.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Carnegie Inst. of Science, Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- AC02-06CH11357; NA0001974; FG02-99ER45775
- OSTI ID:
- 1237736
- Alternate ID(s):
- OSTI ID: 1236399
- Journal Information:
- Journal of Applied Physics, Vol. 119, Issue 4; ISSN 0021-8979
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- ENGLISH
Web of Science
Pressure-induced isosymmetric phase transition in biurea
|
journal | January 2019 |
New dynamic diamond anvil cells for tera-pascal per second fast compression x-ray diffraction experiments
|
journal | June 2019 |
High-pressure studies with x-rays using diamond anvil cells
|
journal | November 2016 |
New dynamic diamond anvil cells for tera-pascal per second fast compression x-ray diffraction experiments
|
text | January 2019 |
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