Strengthening Mechanisms

This chapter starts with an explanation of the concept of strength in engineering materials to introduce to a detailed description of the most important strengthening mechanism of metallic materials, being: strain, grain boundary, solid solution, second phase and fine particle. These mechanisms are explained accordingly to the dislocation theory and the most important rules, along with the relevant equations such as the Hall-Petch law, the rule of mixtures, the interparticle spacing strengthening relation and so on are introduced. The effects of second phase particle shape and distribution on the mechanical strength of materials is discussed. The upper yield strength and strain aging phenomena are described. Furthermore, the martensite hardening behavior in steels is thoroughly described due to its technological importance.