3 1 Introduction 1. Deformation process of polycrystalline materials Deformation process of industrial material consists of three stages Elastic, which is reversible Plastic or permant Fracture§4.1 Introduction 1. Deformation process of polycrystalline materials Deformation process of industrial material consists of three stages: ➢ Elastic, which is reversible ➢ Plastic or permant ➢ Fracture