Thermally activated process in deformed alpha titanium

1988 ◽  
Vol 38 (5) ◽  
pp. 491-493 ◽  
Author(s):  
P. Lukáč ◽  
Z. Trojanová ◽  
F. Chmelík ◽  
M. Hamerský ◽  
V. A. Moskalenko
Keyword(s):  
Thermally Activated ◽  
Alpha Titanium ◽  
Thermally Activated Process

RBS/Channeling Diffusion Studies of High Energy Au Implanted Mg Single Crystals

1991 ◽  
Vol 235 ◽  
Author(s):  
R. C. Da Selva ◽  
M. F. Da Silva ◽  
L. Thomé ◽  
A. A. Melo ◽  
J. C. Soares
Keyword(s):  
Single Crystals ◽  
Temperature Regime ◽  
High Energy ◽  
Back Diffusion ◽  
Thermally Activated ◽  
Diffusion Studies ◽  
Higher Temperature ◽  
Diffusion Behaviour ◽  
Thermally Activated Process

ABSTRACTRBS/channeling analyses of high energy Au implantation into Mg are presented. The diffusion behaviour of Au was studied and the occurrence of essentially two distinct regimes were observed: the segregation regime at lower temperatures correlated with the damage introduced by the high energy implantation and the higher temperature regime as a normal thermally activated process of back-diffusion.

NMR Relaxation Studies of Ferroelectric Colemanite

1973 ◽  
Vol 51 (9) ◽  
pp. 1005-1011 ◽  
Author(s):  
A. Watton ◽  
H. E. Petch ◽  
M. M. Pintar
Keyword(s):  
Phase Transition ◽  
Larmor Frequency ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Mode Frequency ◽  
Spin Lattice Relaxation ◽  
Water Molecules ◽  
Thermally Activated ◽  
Molecular Group ◽  
Thermally Activated Process

Proton spin–lattice relaxation of the Zeeman reservoir in the laboratory and rotating frames and of the dipolar reservoir have been studied in ferroelectric colemanite. These studies indicate the presence of two relaxation mechanisms which can be related to motions of the water molecules. The first, referred to as the flip mode and identified with 180° flips of the water molecules about their H—O—H bisectrices, is characterized by a correlation time and U-shaped relaxation minimum expected for a normal thermally activated process. The second, referred to as the jump mode and associated with a structural configuration change, produces a cusp-shaped dip in the relaxation over a very small temperature range in the vicinity of the phase transition. Above the transition temperature, the jump mode frequency is higher than the Larmor frequency and the relaxation behavior is that expected for two thermally activated processes in the white spectral region. However, in the vicinity of the phase transition, the water molecules are tightly coupled to the structure as a whole and the jump mode frequency is determined by the structural stability of the crystal. In this region its behavior is no longer that of a thermally activated process for an isolated molecular group and its frequency approaches zero critically near the phase transition.

scholarly journals DC Electrical Ageing of XLPE under Hydrostatic Pressure

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Fadila Benlizidia Lalam ◽  
Faouzi Djemmal
Keyword(s):  
Hydrostatic Pressure ◽  
Direct Current ◽  
Atmospheric Pressure ◽  
Pressure Effect ◽  
Power Model ◽  
Lifetime Data ◽  
Confidence Bounds ◽  
Polyethylene Films ◽  
Thermally Activated ◽  
Thermally Activated Process

The experimental electrical ageing, of cross-linked polyethylene films 100 μm thick, was investigated under high hydrostatic pressure of 300 bar and at atmospheric pressure. The tests are conducted on direct current (dc) for up to 1000 h ageing and at temperature of 70°C. The use of the Weibull statistic, with the estimation of confidence bounds at 90%, has shown that the hydrostatic pressure has a real effect on the lifetime. These lifetime data are qualitatively analyzed with the inverse power model. It was found that thermally activated process is able to describe the pressure effect on the electrical ageing of XLPE.

Thermally Activated Dislocation Motion in an AS21 Alloy and Alloy Reinforced with Short Ceramic Fibres Studied at Elevated Temperatures

2013 ◽  
Vol 592-593 ◽  
pp. 71-74
Author(s):  
Zuzana Zdražilová ◽  
Zuzanka Trojanová ◽  
Kristián Máthis ◽  
Pavel Lukáč
Keyword(s):  
Magnesium Alloy ◽  
Stress Relaxation ◽  
Applied Stress ◽  
Elevated Temperatures ◽  
Activation Volume ◽  
Activation Enthalpy ◽  
Dislocation Motion ◽  
Thermally Activated ◽  
Effective Components ◽  
Thermally Activated Process

AS21 magnesium alloy (2.1Al-1Si-balance Mg in wt.%) and the alloy reinforced with short δ-Al2O3fibres (Saffil®) were deformed in compression at temperatures between 23 and 300 °C. Stress relaxation tests were performed in order to reveal features of the thermally activated dislocation motion. Internal and effective components of the applied stress have been estimated. The activation volume decreases with increasing effective stress. The values of the activation volume and the activation enthalpy indicate that the main thermally activated process in the alloy as well as in the composite is the dislocation motion in non-compact planes.

scholarly journals Master Sintering Surface: A practical approach to its construction and utilization for Spark Plasma Sintering prediction

2012 ◽  
Vol 44 (2) ◽  
pp. 169-175 ◽  
Author(s):  
V. Pouchly ◽  
K. Maca ◽  
Y. Xiong ◽  
J.Z. Shen
Keyword(s):  
Spark Plasma Sintering ◽  
Practical Approach ◽  
Alumina Ceramics ◽  
Thermally Activated ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Behaviour ◽  
User Friendly ◽  
Thermally Activated Process

The sintering is a complex thermally activated process, thus any prediction of sintering behaviour is very welcome not only for industrial purposes. Presented paper shows the possibility of densification prediction based on concept of Master Sintering Surface (MSS) for pressure assisted Spark Plasma Sintering (SPS). User friendly software for evaluation of the MSS is presented. The concept was used for densification prediction of alumina ceramics sintered by SPS.

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