你将学到什么
The properties of liquid crystals and how these materials are used in modern display technologies
The presence of defects in all crystals at equilibrium
How defects impact numerous properties of materials—from the conductivity of semiconductors to the strength of structural materials
课程概况
Structure determines so much about a material: its properties, its potential applications, and its performance within those applications. This course is the finale in a three-part series from MIT’s Department of Materials Science and Engineering that explores the structure of a wide variety of materials with current-day engineering applications. Taken together, these three courses provide similar content to MIT’s sophomore-level materials structure curriculum.
Part 3 begins with an exploration of quasi-, plastic, and liquid crystals. Next, we will learn how properties of materials are influenced and can be modified by structural defects. We will show that point defects are present in all crystals at finite temperatures and how their presence governs diffusion in materials. Next, we will explore dislocations in materials. We will introduce the descriptors that are used to describe dislocations, we will learn about dislocation motion and consider how dislocations dramatically affect the strength of materials. Finally, we will explore how defects can be used to strengthen materials, and we will learn about the properties of other structural defects such as stacking faults and grain boundaries.
课程大纲
Part 1: Quasi, Plastic, and Liquid Crystals
Quasi crystals
An introduction to plastic and liquid crystals
Liquid crystal descriptors
Liquid crystal applications
Part 2: Introduction to Point Defects
Thermodynamics of point defects
Vacancies, interstitials, solid solutions and nonequilibrium defects
Part 3: Ionic Point Defects & Diffusion
Kröger-Vink notation
Extrinsic defects
Diffusion
Part 4: Dislocations and Deformation
Introduction to dislocations
Elastic and plastic deformation
Stress and strain
Dislocation descriptors
The Burgers vector
Dislocation motion
Resolved shear stress
Part 5: Strengthening & Surface Energy
Strengthening Mechanisms
Surface free energy
Wulff shape
Part 6: 2-Dimensional Defects
Surface defects
Stacking faults
Grain boundaries
Surface reconstruction
Linear defects in liquid crystals
预备知识
University-level chemistry
3.012S.1x
3.012S.2x