Deformation Behaviors of Metals

This chapter first presents an overview of stress and strain by defining engineering stress, engineering strain, true stress, and true strain, including the relevant mathematical relationships and the curves in the stress–strain plot. A distinction is made between the elastic deformation and the plastic deformation with the aid of a stress–strain curve; here the three moduli (the Young’s modulus E, the plastic modulus H, and the tangent modulus K) are introduced. The six deformation models (linear elastic, linear elastic/plastic, elastic/perfectly plastic, rigid/perfectly plastic, rigid/linear strain hardening, and the power law deformation model) are discussed and illustrated with the aid of sketches. Plastic deformation mechanism is explained with reference to dislocation motion and the deformation by slip. Finally, deformation of single crystal is discussed and analyzed. This chapter contains 11 worked numerical examples, 9 diagrams, 2 tables, 21 formulae/equations, and 11 MCQs with answers provided at the end of the book.