Constituent Diffusion in a Deformable Thermoelastic Solid

1987 ◽  
Vol 54 (2) ◽  
pp. 441-446 ◽  
Author(s):  
S. P. Girrens ◽  
F. W. Smith
Keyword(s):  
Thermal Loading ◽  
Diffusion Theory ◽  
Parent Material ◽  
Β Phase ◽  
High Impurity ◽  
High Impurity Concentration ◽  
Thermoelastic Solid ◽  
Impurity Elements ◽  
Fully Coupled ◽  
Diffusion Problems

Solid mixtures containing initially uniform dilute concentrations of impurity elements may, upon the application of mechanical and thermal loading, develop regions of high impurity concentration that could result in local degradation of material properties. To address these degradation processes, a fully coupled thermomechanical-diffusion theory has been developed to describe the mass transport of mobile constituents driven by gradients in concentration, strain dilatation and temperature in a solid deformable parent material. A finite element code has been assembled to solve plane transient thermomechanical-diffusion problems. The theory presented and the resulting code have been successfully used to model internal hydrogen redistribution in β-phase Ti alloys induced by elastic strain gradients during bending.

Effect of magnetic field on a rotating thermoelastic medium with voids under thermal loading due to laser pulse with energy dissipation

2014 ◽  
Vol 92 (11) ◽  
pp. 1359-1371 ◽  
Author(s):  
Mohamed I.A. Othman ◽  
Magda E.M. Zidan ◽  
Mohamed I.M. Hilal
Keyword(s):  
Magnetic Field ◽  
Laser Pulse ◽  
Thermal Loading ◽  
Volume Fraction ◽  
Plane Surface ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Gaussian Laser Beam ◽  
Thermoelastic Solid ◽  
Non Gaussian

This investigation deals with the rotation of magneto-thermoelastic solid with voids subjected to thermal loading due to laser pulse. The bounding plane surface is heated by a non-Gaussian laser beam. The entire porous medium is rotated with a uniform angular velocity. The problem is studied in the context of Green–Naghdi (GN) theory of types II and III, with the effect of rotation, magnetic field, thermal loading and voids. Normal mode analysis is used to solve the physical problem to obtain the exact expressions for the displacement components, stresses, temperature distribution, and change in the volume fraction field, which have been shown graphically by comparison between two types of GN theory (types II and III) in the presence and the absence of rotation and magnetic field and for two values of time on thermoelastic material with voids.

Resistivity Distribution Characteristics of Metallurgical Silicon Ingot after Directional Solidification

2011 ◽  
Vol 675-677 ◽  
pp. 109-112
Author(s):  
Shu Ang Shi ◽  
Wei Dong ◽  
Shi Hai Sun ◽  
Yi Tan ◽  
Guo Bin Li ◽  
...  
Keyword(s):  
Directional Solidification ◽  
Vertical Section ◽  
Growth Direction ◽  
Silicon Ingot ◽  
Metallurgical Silicon ◽  
High Impurity ◽  
Polarity Transition ◽  
High Impurity Concentration ◽  
Solid Liquid Interface ◽  
Solid Liquid

The distribution of resistivity, impurity and polarity in multicrystalline silicon ingot prepared by directional solidification method was detected. The effect of impurity distribution on resistivity was also researched. The results show that the shapes of equivalence line of resistivity in the cross section and vertical section of the silicon ingot depend on the solid-liquid interface. The resistivity in the vertical section increases with the increasing of solidified height at the beginning of solidification and reaches to maximum at the polarity transition point, then decreases rapidly with the increasing of solidified height and tends to zero on the top of the ingot because of the high impurity concentration. Study proves that the variation of resistivity in the vertical section is mainly relevant to the concentration distribution of the impurities such as Al, B and P in the growth direction.

Comparative Study Between FEA-Based Sequentially-Coupled and Fully-Coupled Thermal Stress Models in a Laser Hardening Process

2013 ◽  
Author(s):  
Suhash Ghosh ◽  
Chittaranjan Sahay ◽  
Joseph Connors
Keyword(s):  
Thermal Stress ◽  
Temperature Distribution ◽  
Stress Analysis ◽  
Thermal Loading ◽  
Thermal Stresses ◽  
Preliminary Investigation ◽  
Hardening Process ◽  
Structural Loading ◽  
Laser Transformation Hardening ◽  
Fully Coupled

Numerous mathematical investigations of laser transformation hardening process have been conducted in the past three decades. The commonly used strategy of a sequentially coupled temperature-stress analysis is to first obtain temperature results from the temperature elements in a thermal loading model, followed by the calculations of thermal stresses from the structural elements under structural loading. Temperature is used as a predefined variable (varies with position and time only) as it is assumed to not change by the stress analysis. Fully coupled thermal-stress analysis is needed when the stress analysis is dependent on the temperature distribution and the temperature distribution depends on the stress solution This paper compares these two finite element (FE) based approaches for modeling temperature and thermal stress evolution in laser transformation hardening of hypoeutectoid steels. The dependence of temperature results on stresses and vice versa at higher temperatures involving significant inelastic strains has been demonstrated. Preliminary investigation reveals that under such circumstances thermal and mechanical solutions must be obtained simultaneously rather than sequentially.

The influence of thermal loading due to laser pulse on generalized micropolar thermoelastic solid with comparison of different theories

2014 ◽  
Vol 10 (3) ◽  
pp. 328-345 ◽  
Author(s):  
Mohamed I.A. Othman ◽  
W.M. Hasona ◽  
Elsayed M. Abd-Elaziz
Keyword(s):  
Laser Pulse ◽  
Thermal Loading ◽  
Plane Surface ◽  
Normal Mode Analysis ◽  
Relaxation Times ◽  
Mode Analysis ◽  
Gaussian Laser Beam ◽  
Content Type ◽  
Thermoelastic Solid ◽  
Non Gaussian

Purpose – The purpose of this paper is to introduce the coupled theory, Lord-Shulman theory with one relaxation time and Green-Lindsay theory with two relaxation times to study the influence of rotation on generalized micropolar thermoelasticity subject to thermal loading due to laser pulse. The bounding plane surface is heated by a non-Gaussian laser beam with pulse duration of 8 ps. Design/methodology/approach – The problem has been solved numerically by using the normal mode analysis. Findings – The thermal shock problem is studied to obtain the exact expressions for the displacement components, force stresses, temperature, couple stresses and micro-rotation. The distributions of the considered variables are illustrated graphically. Comparisons are made with the results predicted by three theories in the presence and absence of laser pulse and for different values of time. Originality/value – Generalized micropolar thermoelastic solid.

Proximity Gettering of Slow Diffuser Contaminants

2013 ◽  
Vol 205-206 ◽  
pp. 271-277 ◽  
Author(s):  
Maria Luisa Polignano ◽  
Isabella Mica ◽  
Elena Cazzini ◽  
Monica Ceresoli ◽  
Davide Codegoni ◽  
...  
Keyword(s):  
Solid Solution ◽  
Impurity Concentration ◽  
Extended Defects ◽  
High Impurity ◽  
High Impurity Concentration ◽  
Silicon Implantation ◽  
And Tungsten

In this paper, we test proximity gettering layers obtained by carbon or silicon implantation for their efficiency in molybdenum and tungsten gettering. DLTS was used to measure the impurity concentration in the solid solution and so to evaluate gettering efficiency. It was found that carbon implantation is effective in capturing these impurities, whereas silicon implantation is not. Extended defects seem not to play an important role in gettering these impurities. In addition, gettering was found to be most effective at high impurity concentration.

scholarly journals Fabrication of non-equilibrium Si: Te and Si: Zn Systems with extremely high impurity concentration by means of laser annealing.

1981 ◽  
Vol 9 (4) ◽  
pp. 434-438
Author(s):  
Kouichi MURAKAMI ◽  
Eiji IKAWA ◽  
A.H. ORABY ◽  
Kenji GAMO ◽  
Susumu NAMBA ◽  
...  
Keyword(s):  
Impurity Concentration ◽  
Laser Annealing ◽  
High Impurity ◽  
High Impurity Concentration ◽  
Non Equilibrium
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