1 Department of Materials Science and Engineering MSE 200-001 - SPRING 2010 MECHANICAL PROPERTIES OF STRUCTURAL MATERIALS SECTION 001: TH 10:15-11:30 AM IN HARRELSON 113 Instructor: Dr. Yuntian Zhu Office: 308 Research Building II (RBII) Phone: 513-0559 Email: [email protected] Web: http://www.mse.ncsu.edu/zhu/ Office Hours: by Appointment TEXTBOOK: Foundations of Materials Science and Engineering, 5th Edition by William F. Smith (4th edition also OK). THE COURSE CONSISTS of a lecture series (MSE 200). MSE 200 is an introduction to the fundamentals, which give rise to the wide spectrum of materials of practical use to engineers, with emphasis on their mechanical behavior. The topics covered in this course are extensive, and many new terms and concepts will be presented. You are expected to learn terminology, be able to present concepts and relationships graphically, and apply your knowledge to solve a variety of simple numerical problems. You must have the fourth edition of the textbook. There will be several supplements to the textbook. The test will cover the assigned sections as well as supplemental materials and homework/example problems. Students will be responsible for all and only materials covered in class. The schedule for lectures and test dates are on the attached MSE 200 schedule page. SCHEDULED TESTS A total of four in-class tests (including the final exam) are given throughout the semester as per the course schedule. The final exam is not comprehensive. Problems covered on the test will be similar to homework problems and questions, and example problems in the textbook. You MUST bring your student ID to all exams to be verified. All exams are closed book. University policy on makeup tests will be strictly enforced. HOMEWORK PROBLEMS will be assigned from the textbook and other sources. You are not required to turn in homework. The homework problems are a critical part of the course and reflect the expectation of your understanding the materials. The homework problem solutions will be posted on the MSE 200 website.2 TOPICAL OUTLINE OF MSE 200 MECHANICAL PROPERTIES OF STRUCTURAL MATERIALS PART I Introduction: Materials and Engineering. Types of materials: metals, polymers, ceramics, composites, and electronic materials. Atomic structure and bonding: structure of the atom, atomic numbers and atomic masses. Electronic structure and electronic notations. Interatomic forces and energies. Types of atomic and molecular bonds: the ionic bond, the covalent bond, the metallic bond, and secondary bonds. Crystal structures and geometry: Crystal lattices and the unit cell. The principal metallic crystal structures: the body-centered cubic, the face-centered cubic, and the hexagonal close-packed structures. Miller’s indices of planes and directions in the cubic system. Atomic packing. Density calculation. Planar and linear atomic densities. Polymorphism. X-Ray diffraction and crystal structure analysis. Crystal imperfections and diffusion: Point defects, solid solutions, vacancies and interstilialcies, line defects (dislocations), Burger’s vector, edge and screw dislocations. Grain boundaries and grain size. Metallography. Rate processes in solids, the activation energy. Atomic diffusion and diffusion mechanisms. Substitutional and interstitial diffusion. Steady state diffusion and Fick’s first law. Transient diffusion and Fick’s second law. Effect of temperature on diffusion rate. Industrial applications of diffusion. PART II Stresses and strains in solids. Normal and shear stresses. Elastic and plastic deformation. The tensile test and the engineering stress-strain diagrams. Young’s modulus, the yield strength, the ultimate tensile strength, the percent elongation and percent reduction in area. True stress and true strain. Hardness and hardness testing. Plastic deformation single crystals. The slip mechanism and dislocations. Slip systems and the critical resolved shear stress. Schmidt’s law. Twinning. Plastic deformation a polycrystalline metals. Effects of plastic deformation on the microstructure of metals. Effects of plastic deformation on the mechanical properties of metals. Cold work and strain hardening. Strengthening by solid solutions. Effect of heating on the microstructure and properties of cold-worked metals. Recovery and crystallization. Hot work. Fracture of metals. Ductile and brittle fracture. Toughness and impact testing. Fracture toughness. Fatigue of metals. The S/N diagram. Mechanisms of fatigue. Stress raisers and stress concentration. Initiation and growth of fatigue cracks. Factors affecting fatigue behavior of metals. Fatigue life of uncracked components, high cycle fatigue and Basquin’s law, low cycle fatigue and Coffin-Manson law. Miner’s rule of fatigue life and cumulative fatigue damage. Fatigue under a combination of static and cyclic loading, the Goodman relationship. Fatigue in cracked components. Crack growth under cyclic loading and Paris’s law. Fatigue life of cracked components. Creep and stress3 rupture in metals. Stages of creep. Effect of stress and temperature on creep behavior. The Larsen-Miller parameter. Stress relaxation. PART III Phase diagrams of pure substances (Unary systems). Gibb’s phase rule of heterogeneous equilibrium. Binary Systems: Systems with unlimited solid solubility (isomorphous). The lever rule. Binary eutectic systems with no solid solubility and eutectic systems with limited solid solubility. Systems with compound and intermediate phases. Systems with peritectics. The invariant reactions, eutectics (and eutectoids) and peritectics (and peritectoids). Applications to typical binary phase diagrams. The Iron-Carbide diagram, the Copper-Zinc diagram and the Aluminum-Copper diagram. Heat treatment of eutectoid steel: The eutectoid reaction in the iron-iron carbide system. The isothermal decomposition of austenite. The T.T.T. diagram. Formation pearlite and bainite. Decomposition of austenite on continuous cooling. Formation of martensite and the martensite lines. The structure of martensite. Annealing, quench hardening,