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Lecture

Mechanical Properties of Materials: Elastic Limit and Dislocations

In course

MSE-101(a): Materials:from chemistry to properties

Ce cours permet l'acquisition des notions essentielles relatives à la structure de la matière, aux équilibres et à la réactivité chimique en liaison avec les propriétés mécaniques, thermiques, électriques et magnétiques des matériaux. ...

Description

This lecture introduces the mechanical properties of materials, focusing on the elastic limit and hardness. It covers topics such as the Young's modulus, types of defects in crystalline materials, dislocations, and the plasticity mechanisms of metals. The discussion includes the impact of dislocations on material deformation, the concept of shear rigidity, and strategies for strengthening materials by blocking dislocation movement.

Instructor

Véronique Michaud

Background: 1994 Habilitation à diriger des recherches ( INPG, France) 1991 PhD in Materials Engineering ( MIT, USA) 1987 Ingénieur Civil des Mines ( Ecole des Mines de Paris, France) Activities: Since January 2018: Associate Dean of Engineering, in charge of Education June 2012-Dec.2017: Head of the Materials Science and Engineering Section Since April 2017: Associate Professor at EPFL 2009-2017 : Professeur Titulaire at EPFL 1997-2009: Researcher at EPFL 1994-1997 : Chef de Travaux au laboratoire MSS-MAT, Ecole Centrale Paris (France) 1991-1994 : Post-doctoral research associate, MIT (USA) Author of about 300 publications of which 140 in peer-reviewed journals

Official source

Ontological neighbourhood

Chemical engineering

Materials science: Deformation of materials

Chemistry

Organic chemistry: Organometallic chemistry

Related concepts (32)

Plasticity (physics)

In physics and materials science, plasticity (also known as plastic deformation) is the ability of a solid material to undergo permanent deformation, a non-reversible change of shape in response to applied forces. For example, a solid piece of metal being bent or pounded into a new shape displays plasticity as permanent changes occur within the material itself. In engineering, the transition from elastic behavior to plastic behavior is known as yielding. Plastic deformation is observed in most materials, particularly metals, soils, rocks, concrete, and foams.

Metal

A metal (from Ancient Greek μέταλλον métallon 'mine, quarry, metal') is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ductile (can be drawn into wires) and malleable (they can be hammered into thin sheets). These properties are the result of the metallic bond between the atoms or molecules of the metal. A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride.

Creep (deformation)

In materials science, creep (sometimes called cold flow) is the tendency of a solid material to undergo slow deformation while subject to persistent mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength of the material. Creep is more severe in materials that are subjected to heat for long periods and generally increase as they near their melting point. The rate of deformation is a function of the material's properties, exposure time, exposure temperature and the applied structural load.

Dislocation

In materials science, a dislocation or Taylor's dislocation is a linear crystallographic defect or irregularity within a crystal structure that contains an abrupt change in the arrangement of atoms. The movement of dislocations allow atoms to slide over each other at low stress levels and is known as glide or slip. The crystalline order is restored on either side of a glide dislocation but the atoms on one side have moved by one position. The crystalline order is not fully restored with a partial dislocation.

Deformation (physics)

In physics and continuum mechanics, deformation is the transformation of a body from a reference configuration to a current configuration. A configuration is a set containing the positions of all particles of the body. A deformation can occur because of external loads, intrinsic activity (e.g. muscle contraction), body forces (such as gravity or electromagnetic forces), or changes in temperature, moisture content, or chemical reactions, etc. Strain is related to deformation in terms of relative displacement of particles in the body that excludes rigid-body motions.

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