| 1 | Overview
Overview of the course structure, which focuses upon the processing-structure-property relationships in metals. The course is designed to start with pure metals, examining the role of (i) deformation and (ii) temperature in governing the structure and properties. Later, complexity is added through (iii) chemical additions, i.e., alloying, and the course culminates with detailed discussions of important alloy systems, most notably, Fe-C. |
| Part I. Deformation in Pure Metals |
| 2 | Background Material
Background material for the course is briefly reviewed, including Miller Indices and Miller-Bravais Indices, metallic bonding and crystal structure, stereographic projections. |
| 3 | Dislocation Structure
Basics of dislocation structure are presented, beginning with a historical overview of how dislocations were discovered. Structure of edge, screw, and mixed dislocations, and the mechanisms by which they propagate strain are covered. Dislocation structures in FCC and HCP metals are described in some detail. |
| 4 | Dislocation Structure (cont.)
More detail on dislocations, including partials, stacking faults, and dislocation intersections are discussed. The stress and strain fields around dislocations are covered in some detail, and the strain energy of the defects as well. |
| 5 | Inter-dislocation Forces
The effect of inter-dislocation forces on microstructure and properties is discussed: pile-ups, annihilation, Frank's rule, dipoles and sub-boundaries, elastic band analogy, Frank-Read sources, etc. |
| 6 | Crystallographic Orientation and Dislocation Behavior
The effect of crystallographic orientation on dislocation behavior is covered; critical resolved shear stress, Schmid analysis, Schmid-law failures in non-FCC metals, cross slip, crystal rotation during deformation. |
| 7 | Work Hardening
Work hardening is discussed, including Orowan looping, Taylor law, the Holloman equation. |
| 8 | Twinning
Twinning is discussed in terms of formal crystallography; twinning strain and stress are described. |
| Part II. Thermal Effects on Pure Metal Structure and Properties |
| 9 | Thermal Effects
This lecture moves the course from (i) deformation to (ii) thermal effects, focusing upon microstructural evolution in pure metals at temperatures above about 1/3 of the melting point. Dislocation climb is discussed mechanistically and mathematically, and the stored dislocation energy relieved by annealing is calculated. |
| 10 | Ensemble Effects
Moving from single dislocations to ensemble effects, recovery and polygonization are reviewed. Recrystallization is also introduced and described phenomenologically. |
| 11 | Exam I |
| 12 | The Johnson-Mehl-Avrami-Kolmogorov Equation
The Johnson-Mehl-Avrami-Kolmogorov equation is derived in detail, and used to rationalize the strain, temperature, and time dependencies of recrystallization. |
| Part III. Alloying |
| 13 | Solid-Solution Alloys
The second half of the course begins by adding (iii) alloying and chemical effects on metal structure and behavior. This lecture covers solid-solution alloys, focusing upon solute-dislocation interactions via stress-field and modulus effects. |
| 14 | Dislocation-Solute Interactions
Individual dislocation-solute interactions are extrapolated to ensemble effects, including "upper yield points" during mechanical testing, serrated flow, strain aging, and viscous drag. |
| 15 | Precipitation - Part 1
Solid solution strengthening is summarized and compared to the new concept for this lecture: precipitation strengthening. Thermodynamics and kinetics of precipitation are briefly reviewed, and the mechanics of dislocation-precipitate interaction are discussed. |
| 16 | Precipitation - Part 2
Power laws for various precipitation-dislocation interactions are derived, and used to develop the cutting-to-bowing transition. Coherent vs. incoherent interfaces are discussed in terms of strengthening. |
| 17 | Precipitation - Part 3
Specific precipitation strengthened alloys are discussed, focusing on the idea of designing an ideal precipitation-strengthened structure. Kinetics of precipitation and ripening are coupled with mechanical equations. GP zones; Ni-Al alloys, complexities in ternary systems, elastic strain fields, dispersion strengthening, are covered as extensions of the simpler models. |
| 18 | Alloy Strengthening
This lecture continues the discussion of second-phase additions to metals, but focuses on coarser microstructures, starting with a survey of engineering alloy microstructures. Load transfer is presented as a general mechanism for strengthening, and the rule-of-mixtures is derived. |
| 19 | Ductility and Toughness
With a detailed understanding of strength in alloys, this lecture begins to address the issue of ductility and toughness. Necking and cleavage cracking are discussed in terms of prior concepts. |
| 20 | Cracking
Cracking is discussed in terms of the Griffith derivation and fracture toughness. Mode II and II failure and fracture mechanism maps are presented. |
| 21 | Fatigue Strength and Failure
Fatigue strength and failure mechanisms are presented. A survey of mechanical and biomechanical component fatigue failures is given. |
| Part IV. Specific Engineering Alloys |
| 22 | Phase Transformations
Beginning with the Fe-C phase diagram, the many possible phase transformations of steel are discussed. The crystallography and kinetics of the transformations are discussed at length. |
| 23 | Applications of Course Concepts
Martensite formation is covered. The relationships between microstructure and strength, toughness, and ductility is presented in terms of the concepts developed throughout the course. |
| 24 | Exam II |
| 25 | Student's Choice of Alloy Systems
This lecture covers in detail one more alloy system of practical significance, chosen by the students. Titanium or aluminum-scandium alloys are popular choices. |