On the determination of apparent activation energies of viscoelastic deformation processes using the instantaneous temperature-change experiment

1978 ◽  
Vol 17 (5) ◽  
pp. 538-551 ◽  
Author(s):  
C. J. Hooley ◽  
R. E. Cohen
Keyword(s):  
Temperature Change ◽  
Activation Energies ◽  
Viscoelastic Deformation ◽  
Deformation Processes ◽  
Instantaneous Temperature ◽  
Apparent Activation Energies

scholarly journals Simple and Exact Determination of Apparent Activation Energies of Electrode Processes.

1981 ◽  
Vol 35b ◽  
pp. 51-52 ◽  
Author(s):  
Vernon D. Parker ◽  
S. Nordlund ◽  
B. C. Johansson ◽  
H. Baltscheffsky ◽  
Anders Rane
Keyword(s):  
Activation Energies ◽  
Electrode Processes ◽  
Exact Determination ◽  
Apparent Activation Energies

Rapid Determination of Apparent Activation Energies in Chemical Vapor Deposition

1983 ◽  
Vol 130 (1) ◽  
pp. 157-160 ◽  
Author(s):  
G. Leyendecker ◽  
H. Noll ◽  
D. Bäuerle ◽  
P. Geittner ◽  
H. Lydtin
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Rapid Determination ◽  
Chemical Vapor ◽  
Activation Energies ◽  
Apparent Activation Energies

Kinetics of Subcritical Crack Growth and Deformation in a High Strength Steel

1973 ◽  
Vol 95 (1) ◽  
pp. 2-9 ◽  
Author(s):  
J. D. Landes ◽  
R. P. Wei
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Activation Energies ◽  
Steady State Creep ◽  
Deformation Kinetics ◽  
Deformation Processes ◽  
Apparent Activation Energies ◽  
Kinetics Of

The kinetics of subcritical crack growth under sustained loading in a chemically inert environment (dehumidified argon) and the companion deformation kinetics were determined to examine the possible relationship between the crack growth and deformation processes in an AISI 4340 steel tempered at 400 deg F (∼205 degC). Crack growth experiments were carried out over a range of temperatures from 20 to 140 deg C, using the crack tip stress intensity factor K to chacterize the mechanical crack driving force. Deformation kinetics were determined as a function of deformed structure either at constant load or by a strain rate cycling procedure over the same range of temperatures. Detectable crack growth (with rates above 10−5 ipm) in dehumidified argon occurred at K levels exceeding about 70 percent of Kc at room temperature and 50 percent of Kc at the higher temperatures. Crack growth exhibited transient, steady-state and tertiary stages of growth, akin to creep, in agreement with the results of Li, et al. Experimental data indicate that subcritical crack growth in dehumidified argon is controlled by thermally activated processes, with apparent activation energies in the range of 11,000 to 18,000 cal/mole. This range of apparent activation energies is in general agreement with an observed range of 12,000 to 28,000 cal/mole for steady-state creep in this material. The apparent activation energies for steady-state creep were found to be dependent on flow stress and structure. Based on the similarity between the observed crack growth and deformation behaviors and on the order of magnitude agreement between the apparent activation energies, it is reasonable to consider that subcritical crack growth in inert environments is controlled by the time dependent deformation processes occurring at the crack tip. A model for relating steady-state crack growth and steady-state creep is suggested, and is shown to correlate well with experimental data.

New 3DXRD Results on Recrystallization and Grain Growth

2012 ◽  
Vol 715-716 ◽  
pp. 393-398 ◽  
Author(s):  
Dorte Juul Jensen ◽  
S.S. West ◽  
S.O. Poulsen ◽  
Søren Schmidt
Keyword(s):  
Grain Growth ◽  
Activation Energies ◽  
3D Microstructure ◽  
Apparent Activation Energies

New in-situ 3DXRD results obtained since the last Rex&GG conference are presented and discussed. This includes: Documentation of the formation of nuclei with new orientations, determination of apparent activation energies for individual bulk grains during recrystallization and evolution in the 3D microstructure during grain growth.

scholarly journals Migration of mineral oil in elastomers

2021 ◽  
Author(s):  
Tobias Förster ◽  
Artur Blivernitz
Keyword(s):  
Diffusion Coefficients ◽  
Mineral Oil ◽  
Activation Energies ◽  
Concentration Profiles ◽  
Small Reservoir ◽  
Experimental Procedure ◽  
Mineral Oils ◽  
The Absolute ◽  
Suitable Measure

AbstractThis work describes a newly introduced experimental procedure to quantify the diffusion progress of mineral oils locally resolved in NBR. Diffusion of reference oils IRM 901, IRM 902 and IRM 903 in NBR with various acrylonitrile contents was investigated. Classical sorption experiments were performed as a basic characterization and compared to the newly introduced method. Here, elastomer specimens are only being dipped with the bottom in a relatively small reservoir of mineral oil. This provides a determination of locally resolved concentration profiles of mineral oils, and the calculation of diffusion coefficients. These diffusion coefficients follow the same trends like those determined via sorption experiments. Despite differences in the absolute numbers, activation energies of diffusion can be applied as a suitable measure for the compatibility of elastomers and fluids.

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