Lec 3 Plastic Deformation And Mechanical Properties Of Metal Pdf Pdf 1 chapter 6: mechanical properties of metals outline introduction concepts of stress and strain elastic deformation. • stress strain behavior • elastic properties of materials. plastic deformation. • yield and yield strength • ductility • resilience • toughness. concepts of stress and strain. Lec 3 plastic deformation and mechanical properties of metal (2).pdf free download as pdf file (.pdf), text file (.txt) or read online for free. scribd is the world's largest social reading and publishing site.
Ppt Mechanical Properties Lec 3 2 1 Stress And Strain What Are They • plastic deformation • number of dislocations in the structure. • macroscopic plastic deformation strain depends on the ability of dislocations to move • bond breaking and re bonding process • reduction the ability of dislocation movement , means increase in hardness and strength • pure aluminum is weaker and softer than al 6061. Theoretical basis for elastic deformation – reversible displacements of atoms from their equilibrium positions – stretching of atomic bonds. elastic moduli measures stiffness of material. it can also be a measure of resistance to separation of adjacent atoms. elastic modulus = fn (inter atomic forces) = fn (inter atomic distance) = fn. Hardness: a measure of the resistance of a material to plastic (permanent) deformation. measured by indentation. indenter material (ball, pyramid, cone) is harder than the material being tested (i.e.: tungsten carbide, diamond) indenter is pressed at 90o. hardness is based on the depth of the impression or its cross sectional area. Elastic behavior: this reversible behavior often shows a linear relation between stress and strain. to minimize deformation, select a material with a large elastic modulus (e or g). plastic behavior: this permanent deformation behavior occurs when the tensile (or compressive) uniaxial stress reaches σy.
Mechanical Properties Of Metals Elastic And Plastic Deformation Hardness: a measure of the resistance of a material to plastic (permanent) deformation. measured by indentation. indenter material (ball, pyramid, cone) is harder than the material being tested (i.e.: tungsten carbide, diamond) indenter is pressed at 90o. hardness is based on the depth of the impression or its cross sectional area. Elastic behavior: this reversible behavior often shows a linear relation between stress and strain. to minimize deformation, select a material with a large elastic modulus (e or g). plastic behavior: this permanent deformation behavior occurs when the tensile (or compressive) uniaxial stress reaches σy. Two prominent mechanisms of plastic deformation, namely slip and twinning . slip is the prominent mechanism of plastic deformation in metals. it involves sliding of blocks of crystal over one other along definite crystallographic planes, called slip planes. it is analogous to a deck of cards when it is pushed from one end. Elastic deformation: poisson’s ratio. materials subject to tension shrink laterally. those subject to compression, bulge. the ratio of lateral and axial strains is called the poisson's ratio υ. sign in the above equations shows that lateral strain is in opposite sense to longitudinal strain. υ is dimensionless.
Mechanical Properties Of Metals Stress And Strain In Metals Ppt Download Two prominent mechanisms of plastic deformation, namely slip and twinning . slip is the prominent mechanism of plastic deformation in metals. it involves sliding of blocks of crystal over one other along definite crystallographic planes, called slip planes. it is analogous to a deck of cards when it is pushed from one end. Elastic deformation: poisson’s ratio. materials subject to tension shrink laterally. those subject to compression, bulge. the ratio of lateral and axial strains is called the poisson's ratio υ. sign in the above equations shows that lateral strain is in opposite sense to longitudinal strain. υ is dimensionless.
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