Lecture

Diffusion in Alloys: Diluted and Binary Alloys

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

In course

MSE-209: Transfer phenomena in materials science

Ce cours porte sur le transfert de la chaleur par conduction, convection et rayonnement, ainsi que sur la diffusion à l'état solide. D'après les règles phénoménologiques (Equations de Fourrier et Fick), des problèmes de solution 1-D et 2-D ainsi que modèle ...

Description

This lecture covers the calculation of diffusion in alloys, including diluted and binary alloys, chemical diffusion, phase separation, and the effects of concentration on intermolecular forces. It also discusses the impact of solute addition on self-diffusion, the concept of intrinsic diffusion coefficient, and the thermodynamic factors influencing diffusion. The lecture further explores the free energy of mixing, phase separation in materials, and the formation of two-phase systems in binary alloys. Additionally, it delves into the mechanisms of spinodal decomposition and germination and growth in phase separation. The lecture concludes with examples of phase separation in lipid mixtures and the diffusion of bath water into the skin.

This video is available exclusively on Mediaspace for a restricted audience. Please log in to MediaSpace to access it if you have the necessary permissions.

Watch on Mediaspace

Official source

Ontological neighbourhood

Physics

Thermodynamics: Statistical mechanics

Related concepts (27)

Diffusion

Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical potential. It is possible to diffuse "uphill" from a region of lower concentration to a region of higher concentration, like in spinodal decomposition. Diffusion is a stochastic process due to the inherent randomness of the diffusing entity and can be used to model many real-life stochastic scenarios.

Lipid bilayer

The lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around all cells. The cell membranes of almost all organisms and many viruses are made of a lipid bilayer, as are the nuclear membrane surrounding the cell nucleus, and membranes of the membrane-bound organelles in the cell. The lipid bilayer is the barrier that keeps ions, proteins and other molecules where they are needed and prevents them from diffusing into areas where they should not be.

Lipid polymorphism

Polymorphism in biophysics is the ability of lipids to aggregate in a variety of ways, giving rise to structures of different shapes, known as "phases". This can be in the form of spheres of lipid molecules (micelles), pairs of layers that face one another (lamellar phase, observed in biological systems as a lipid bilayer), a tubular arrangement (hexagonal), or various cubic phases (Fdm, Imm, Iam, Pnm, and Pmm being those discovered so far). More complicated aggregations have also been observed, such as rhombohedral, tetragonal and orthorhombic phases.

Lipid bilayer phase behavior

One property of a lipid bilayer is the relative mobility (fluidity) of the individual lipid molecules and how this mobility changes with temperature. This response is known as the phase behavior of the bilayer. Broadly, at a given temperature a lipid bilayer can exist in either a liquid or a solid phase. The solid phase is commonly referred to as a “gel” phase. All lipids have a characteristic temperature at which they undergo a transition (melt) from the gel to liquid phase.

Lipid bilayer fusion

In membrane biology, fusion is the process by which two initially distinct lipid bilayers merge their hydrophobic cores, resulting in one interconnected structure. If this fusion proceeds completely through both leaflets of both bilayers, an aqueous bridge is formed and the internal contents of the two structures can mix. Alternatively, if only one leaflet from each bilayer is involved in the fusion process, the bilayers are said to be hemifused.

Related lectures (64)

Phase Equilibria: Understanding Vapor-Liquid Separation

Provides an overview of vapor-liquid phase diagrams and their role in separation processes, focusing on phase equilibria and the Gibbs phase rule.

Thermodynamics: Exploring Thermodynamic Potentials and Equilibrium States

Covers thermodynamic potentials and their role in system equilibrium with reservoirs.

Computational Alloy Design

Explores the design of high-performance alloys, the materials development process, multi-component systems, ICME, CALPHAD approach, and experimental phase diagram investigation.

Thermodynamic Modeling: Real Solutions

Explores thermodynamic modeling of real solutions in materials science, focusing on regular and sublattice models.

Phase Transitions: Understanding Thermodynamic Stability