Deformation properties of construction materials are of great importance in selecting and using materials. Thus, it is aimed to give the necessary information for the better explanation of the behaviors of these materials. It is aimed to give information about the behaviors of these materials that the students of structural engineering should need in designing and researching.

İntroduction; needs for material science.Factors that cause reduction of strength.Mechanical behaviors of rigid bodies; elastic behavior, plastic behavior and viscoelastic behavior. Ideal bodies and mechanical models; elastic body (Hooke Model), rigid plastic body (Saint-Venant Model), elasto-plastic body, rigid elasto-plastic body, viscose body (Newton Model), viscoelastic body. Stress State: stress tensor, prime stresses and prime axes. Maximum shear stresses. Deformation state and constitutive equations, generalized Hooke's Law, finite deformation, viscoelasticity (Rheological Modeller); Kelvin body, Maxwell body, Burger body. Plastic behavior, plastic deformation, microplasticity of single crystals.Dislocations: Flow resistance in perfect crystal, types of dislocations, properties of dislocations, dislocation geometry, interaction of dislocations.Plastic shape change of multicrystalline metals.Strengthening procedures in metallic materials. The true strain-deformation diagram of steel. Fracture Criteria: Crisp behavior, ductile behavior, fracture hypotheses (Griffith theory, Tresca and Von Mises criterion), experimental determination of flow conditions. Fatigue behavior.