Showing 2 results for Arrhenius Relation
Seyed Mohammad Mirghasemi, Ehsan Mohammad Sahrifi, Gholam Hossein Borhani, Mirtaher Seyed Beigi,
Volume 21, Issue 4 (12-2024)
Abstract
In this study, the hot deformation and dynamic recrystallization behavior of low carbon steel containing 21 ppm boron was investigated. After homogenizing the samples at 1250 ℃ for 1-hour, hot compression tests were conducted at temperatures ranging from 850 ℃ to 1150 ℃ and strain rates from 0.01 to 10 s⁻¹, resulting in strain-stress flow curves. Following corrections, calculations and modeling were performed based on Arrhenius equations. Among them, the hyperbolic sine relationship provided the most accurate estimate and was selected as the valid model for the applied strain range. According to this model, the deformation activation energy (Q), was determined to be 293.37 KJ/mol. Additionally, critical and peak stress and strain values were obtained for each temperature and strain rate, and power relationships were established to describe their variation with respect to the Zener-Hollomon parameter (Z). Recrystallization fractions were derived by comparing the hypothetical recovery curves with the material flow curves, and the results were successfully modeled using the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. The Avrami exponent was measured at approximately 2, indicating that nucleation predominantly occurred at grain boundaries. Microstructural analysis revealed that at higher Z values, recrystallization occurred along with a fraction of elongated grains, while lower Z values resulted in a greater fraction of equiaxed dynamic recrystallization (DRX) grains. The average grain sizes after compression tests at 950 ℃, 1050 ℃, and 1150 ℃ were measured as 21.9 µm, 30.4 µm, and 33.6 µm respectively at a strain rate of 0.1 s⁻¹, and 17.7 µm, 28.7 µm, and 31.3 µm at 1 s⁻¹. The overall microstructure displayed a more uniform grain size distribution with increasing deformation temperature.
Krishna Jyothi N, Keerthi M., Gnana Kiran M., Venkata Kamesh Vinjamuri, Prakash Babu Kanakavalli, Krupakaran R.l, Nandini P.s.v., Rao M.c., D. Madhavi Latha, Mahamuda Sk.,
Volume 22, Issue 4 (12-2025)
Abstract
This research systematically examines the structural, electrical, and optical characteristics of Tamarind Seed Polysaccharide (TSP)--based biopolymer electrolytes that are doped with varying concentrations of sodium iodide (NaI). Composite films were synthesized using the solution cast technique in weight percent ratios of TSP: NaI (100:0, 90:10, 80:20, 70:30) and subsequently characterized employing X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, and impedance analysis. The XRD analysis indicated that the 80:20 composition displayed the highest degree of amorphousness, which is associated with improved ionic conductivity and reduced crystallite size. The FTIR analysis corroborated the occurrence of complexation between TSP and NaI, while the temperature-dependent conductivity measurements conformed to Arrhenius behaviour, with the 80:20 film achieving the ionic conductivity (1.97x10⁻4 S/cm) and the lowest activation energy (0.69 eV). Optical absorption investigations revealed a decrease in the bandgap from 3.92 (pure TSP) to 2.68 eV (80:20 film). Minimum optical energy bandgaps were achieved for the optimized film. Opto-dielectric investigations further demonstrated that the 80:20 formulation exhibited optimal dielectric permittivity and loss. The results underscore the potential applicability of TSP–NaI biopolymer systems as sustainable, high-performance polymer electrolytes.
