scholarly journals Effect of 4 GPa pressure treatment on the solid state transformation kinetics of T8 steel in heating process

2012 ◽  
Vol 61 (19) ◽  
pp. 196203
Author(s):  
Chen Yan ◽  
Li Ya-Li ◽  
Liu Jian-Hua ◽  
Zhang Rui-Jun
Keyword(s):  
Solid State ◽  
Heating Process ◽  
Pressure Treatment ◽  
Transformation Kinetics ◽  
State Transformation ◽  
Solid State Transformation ◽  
Kinetics Of

Nucleation kinetics of ellipsoidal shaped nucleus on a dislocation during a solid state transformation

1988 ◽  
Vol 22 (8) ◽  
pp. 1189-1193
Author(s):  
P. Sureshkumar ◽  
C. Subramanian ◽  
P. Ramasamy ◽  
M.N. Shetty
Keyword(s):  
Solid State ◽  
Nucleation Kinetics ◽  
State Transformation ◽  
Solid State Transformation ◽  
Kinetics Of

The effect of geometrical assumptions in modeling solid-state transformation kinetics

1998 ◽  
Vol 29 (12) ◽  
pp. 2925-2931 ◽  
Author(s):  
Yvonne van Leeuwen ◽  
Simone Vooijs ◽  
Jilt Sietsma ◽  
Sybrand Van Der Zwaag
Keyword(s):  
Solid State ◽  
Transformation Kinetics ◽  
State Transformation ◽  
Solid State Transformation

Predicting Solid-State Phase Transformations during Welding of Ferritic Steels

2012 ◽  
Vol 706-709 ◽  
pp. 1403-1408 ◽  
Author(s):  
Cory J. Hamelin ◽  
Ondrej Muránsky ◽  
Philip Bendeich ◽  
Ken Short ◽  
Lyndon Edwards
Keyword(s):  
Solid State ◽  
Phase Transformations ◽  
Current Model ◽  
Input Parameter ◽  
Isothermal Transformation ◽  
Ferritic Steels ◽  
Correct Identification ◽  
Transformation Kinetics ◽  
State Transformation ◽  
Solid State Transformation

The current work presents the numerical analysis of solid-state transformation kinetics relating to conventional welding of ferritic steels, with the aim of predicting the constituent phases in both the fusion zone and the heat affected zone (HAZ) of the weldment. The analysis begins with predictions of isothermal transformation kinetics using thermodynamic principles, such that the chemical composition of the parent metal is the sole user-defined input. The data is then converted to anisothermal transformation kinetics using the Scheil-Avrami additive rule, including the effects of peak temperature and austenite grain growth. Subroutines developed for the Abaqus finite element package use the semi-empirical approach described to predict phase transformations in SA508 Gr.3 Cl.1 steel. To study the effect of the cooling rates and the ability of the current model to predict the final microstructure, two weld samples were subjected to autogenous beam TIG welds under a fast (TG5-F, 5.00 mm/s) and slow (TG5-S, 1.25 mm/s) torch speed. Model validation is carried out by direct comparison with microstructural observations and hardness measurements (via nanoindentation) of the fusion and heat affected zones in both welds. Excellent agreement between the measured and predicted hardness has been found for both weld samples. Additionally, it is shown that the correct identification of the partial austenisation region is a crucial input parameter.

The kinetics of the solid state transformation of racemic to optically active 1,1′-binaphthyl

1977 ◽  
Vol 55 (5) ◽  
pp. 889-894 ◽  
Author(s):  
Keith R. Wilson ◽  
Richard E. Pincock
Keyword(s):  
Solid State ◽  
Active Phase ◽  
Reaction Rates ◽  
Optically Active ◽  
State Transformation ◽  
Arrhenius Activation Energy ◽  
Solid State Transformation ◽  
Crystal Forms ◽  
Spontaneous Nucleation ◽  
Kinetics Of

Rates of the solid state reaction which thermally converts racemic to optically active 1,1′-binaphthyl (mp 158 °C) have been determined at temperatures between 105 and 135 °C using polycrystalline samples. The presence of a sufficiently uniform distribution of enantiomorphic seed crystals results in a smooth conversion of the racemate to the eutectic crystal forms of binaphthyl. Although it is possible to force the resolution reaction almost to completion at higher temperatures (150 °C) where the melt phase is an intermediate, lower final specific rotations are obtained when only solid phases are involved (below 145 °C) because of the independent nucleation of racemic material from the reacting crystals. Both spontaneous nucleation and reaction rates in the solid state were increased by grinding the initially prepared samples and were decreased by the storage of samples. The Arrhenius activation energy of this phase transformation giving optically active product is ca. 60 kcal/mol in a variety of different samples. This is consistent with a mechanism in which a molecule of 1,1′-binaphthyl attains considerable freedom from the racemic solid in order to interconvert to its enantiomer and add to the growing optically active phase.

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