Course Out Line

Plastic Deformation of Metals Course out line

Course out line • Crystalline Material • Crystallography--- Crystal defects • Deformation -----i) Elastic ii) Plastic or permanent Mechanism of Plastic deformation: i) Slip ii) Twinning

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Resolved Shear Stress for Slip Strength of a perfect crystal Role of a dislocation in deformation Dislocation, its observation, Climb and Cross slip, gogs and Kinks. • Multiplication of Dislocation

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Dislocation in F.C.C Structure Perfect and Partial Dislocation Stair Rod Dislocation Thomson Tetrahedron Deformation in single crystal and polycrystalline material.

Cottrell (1953) • “Few problems of crystal plasticity have proved more challenging than work hardening. It is a spectacular effect, for example enabling the yield strength of pure copper and aluminum crystals to be raised a hundred fold. Also, it occupies a central place in the subject, being related both to the nature of the slip process and to processes such as recrystallisation and creep. It was the first problem to be attempted by the dislocation theory of slip and may well prove the last to be solved.”

• Strengthening Mechansim • Creep, Super plasticity, Fatigue .