Mechanical Properties of Structural Materials
Section 002: TH 11:45-01:00 in
Harrelson 100 Instructor: Dr. Yuntian Zhu
Office: 308 Research Building II (RBII)
Phone: 513-0559
Email: ytzhu@ncsu.edu
Office Hours: TBA
TEXTBOOK: Foundations of Materials
Science and Engineering, 4th Edition by
William F. Smith
The course consists of a lecture series (MSE 200) and a problem session (MSE 200P).
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 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. Apart from the problems sessions the
homework problem solutions will be posted on the MSE 200 website.
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. MillerÕs 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),
BurgerÕs 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 FickÕs first law. Transient diffusion and FickÕs
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.
YoungÕs 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.
SchmidtÕs 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 BasquinÕs law, low cycle
fatigue and Coffin-Manson law. MinerÕs 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 ParisÕs law. Fatigue life of cracked components. Creep and stress
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). GibbÕs 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, and austempering. The hardness of martensite.
Tempering of martensite. Heat treatment of noneutectoid plain carbon steel.
T.T.T. diagrams of alloy steels. Hardenability of steel and the end-quench
test.
The
aluminum-rich end of the Aluminum-Copper diagram. The process of precipitation
(or Age) hardening and its application to the aluminum-copper alloys. Solution
treatment, quenching and aging. Artificial (or forced) aging and over-aging.
The mechanism of precipitation hardening in Aluminum-Copper alloys.
Supersaturation, formation of G-P zones, coherent and incoherent
precipitates.
Part IV
Polymeric
materials: Polymerization reactions. The degree of polymerization. Addition
polymerization and copolymers. Condensation polarization. Structure of partly
crystalline polymers. Stereoisomerism. Linear and network polymers. Examples of
engineering thermoplastics and thermosets. Elastomers and vulcanization.
Mechanical properties of polymeric materials in relation to structure. Stress
relaxation.
Ceramic
materials: Ceramic crystal structures. Diamond and graphite. Structure of AX
compounds: The cesium chloride structure, the sodium chloride structure, the
silicon carbide structure. Structure of AX2 compounds, the calcium
fluoride structure. The Perovskite (BaTiO3) structure. Silicate
structures. The SiO4 tetrahedron. Transformation toughening.
Glasses: The glass transition temperature. Structure of glass. Network formers,
modifiers, and intermediates. Mechanical properties of glass. Strengthening of
glasses by tempering and chemical treatment.
Composite
materials: Classification composites: particle and fiber reinforcement. Upper
and lower bounds of composite material properties. Density of composites.
Unidirectional and laminated fiber composites. Longitudinal and transverse
YoungÕs moduli of unidirectional fiber composites. Strength of fiber
composites. Thermal expansion of composite materials