scholarly journals Role of metastable states in phase ordering dynamics

1997 ◽  
Vol 38 (8) ◽  
pp. 595-600 ◽  
Author(s):  
R. M. L Evans ◽  
W. C. K Poon ◽  
M. E Cates
Keyword(s):  
Metastable States ◽  
Phase Ordering

Role of the Kinetic Relation in a Phase Transition-Based Model for Mechanical Unfolding in Macromolecules

2010 ◽  
Author(s):  
Ritwik Raj ◽  
Prashant K. Purohit
Keyword(s):  
Phase Transition ◽  
Driving Force ◽  
Metastable States ◽  
Force Extension ◽  
Kinetic Relation ◽  
One Dimensional ◽  
Applied Tension ◽  
Thermodynamic Driving Force ◽  
Macro Molecule

We present applications of a model developed to describe unfolding in macromolecules under an axial force. We show how different experimentally observed force-extension behaviors can be reproduced within a common theoretical framework. We propose that the unfolding occurs via the motion of a folded/unfolded interface along the length of the molecule. The molecules are modeled as one-dimensional continua capable of existing in two metastable states under an applied tension. The interface separates these two metastable states and represents a jump in stretch, which is related to applied force by the worm-like-chain relation. The mechanics of the interface are governed by the Abeyaratne-Knowles theory of phase transitions. The thermodynamic driving force controls the motion of the interface via an equation called the kinetic relation. By choosing an appropriate kinetic relation for the unfolding conditions and the macro-molecule under consideration, we have been able to generate a variety of unfolding processes in macromolecules.

The Effects of Substitutional Additions on Creep Behavior of Tetragonal and Hexagonal Nb-Silicides

2002 ◽  
Vol 753 ◽  
Author(s):  
B. P. Bewlay ◽  
C. L. Briant ◽  
E. T. Sylven ◽  
M. R. Jackson
Keyword(s):  
Creep Behavior ◽  
High Strength ◽  
Aircraft Engine ◽  
Great Promise ◽  
Silicide Phase ◽  
Monolithic Phases ◽  
Phase Ordering ◽  
The Stability

ABSTRACTNb-silicide based in-situ composites combine a ductile Nb-based solid solution with high-strength silicides, and they show great promise for aircraft engine applications. The Nb-silicide controls the high-temperature creep behavior of the composite. Previous work has shown that the silicide composition has an important effect on the creep rate, with particular attention on the role of Ti and Hf additions. The aim of the present study is to understand the effects of the substitutional elements on the stability of the silicide phase, ordering in the crystal lattice, including the hP16-tI32 transition, and the creep behavior of the monolithic phases. To pursue this goal monolithic alloys with a range of compositions were prepared and the creep rates were measured at temperatures of 1100–1350°C. The stress sensitivities of the creep rates of the monolithic phases were also determined.

Two-dimensional atom-phonon coupling model for spin conversion: role of metastable states

2011 ◽  
Vol 83 (2) ◽  
pp. 115-132 ◽  
Author(s):  
J. A. Nasser ◽  
S. Topçu ◽  
L. Chassagne ◽  
M. Wakim ◽  
B. Bennali ◽  
...  
Keyword(s):  
Coupling Model ◽  
Metastable States ◽  
Two Dimensional ◽  
Phonon Coupling ◽  
Spin Conversion

Role of Film-Substrate Interaction in Determining the Morphology of Thin Films

1987 ◽  
Vol 103 ◽  
Author(s):  
Marcia H. Grabow ◽  
George H. Gilmer
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Computer Simulations ◽  
Substrate Binding ◽  
Equilibrium Structure ◽  
Metastable States ◽  
Growth Mode ◽  
Substrate Interaction ◽  
Film Substrate

ABSTRACTThe equilibrium structure and metastable states of thin films have been investigated using molecular dynamics computer simulations. The energy as a function of coverage for a variety of film/substrate systems has been determined, and this information has been used to determine the growth mode and the conditions under which the film is dislocation free. In particular, the influence of the strength of the film-substrate binding will be discussed.

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