Les infos clés
En résumé
Structure determines so much about a material: its properties, its potential applications, and its performance within those applications. This course from MIT’s Department of Materials Science and Engineering explores the structure of a wide variety of materials with current-day engineering applications.
The course begins with an introduction to amorphous materials. We explore glasses and polymers, learn about the factors that influence their structure, and learn how materials scientists measure and describe the structure of these materials.
Then we begin a discussion of the crystalline state, exploring what it means for a material to be crystalline, how we describe directions in a crystal, and how we can determine the structure of crystal through x-ray diffraction. We explore the underlying crystalline structures that underpin so many of the materials that surround us. Finally, we look at how tensors can be used to represent the properties of three-dimensional materials, and we consider how symmetry places constraints on the properties of materials.
We move on to an exploration of quasi-, plastic, and liquid crystals. Then, we learn about the point defects that are present in all crystals, and we will learn how the presence of these defects lead to diffusion in materials. Next, we will explore dislocations in materials. We will introduce the descriptors that we use to describe dislocations, we will learn about dislocation motion, and will 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 higher-order defects such as stacking faults and grain boundaries.
- How we characterize the structure of glasses and polymers
- The principles of x-ray diffraction that allow us to probe the structure of crystals
- How the symmetry of a material influences its materials properties
- The properties of liquid crystals and how these materials are used in modern display technologies
- How defects impact numerous properties of materials—from the conductivity of semiconductors to the strength of structural materials
Les prérequis
- University-level chemistry
- Single-variable calculus
- Some basic linear algebra
Le programme
Part 1: An Introduction to Materials Science
- Structure of materials roadmap
- States of matter and bonding
Part 2: Descriptors
- Descriptors: concept and function
- Free volume
- Pair distribution function
Part 3: Glasses
- Glass processing methods
- Continuous network model
- Network modifiers
Part 4: Polymers
- Random walk model
- Chain-to-chain end distance
- Order and disorder in polymers
Part 5: An Introduction to the Crystalline State
- Translational symmetry
- The crystalline state in 2D
- The crystalline state in 3D
Part 6: Real and Reciprocal Space
- Miller indices
- Real space
- Reciprocal space
Part 7: X-Ray Diffraction
- Bragg’s Law
- Diffraction examples
Part 8: Symmetry in 2D Crystals
- Translation, mirror, glide and rotation symmetry
Part 9: Point groups in 2D
- Allowed rotational symmetries in crystals
The 10 2D point groups
- An introduction to crystallographic notation
Part 10: Plane groups in 2D
- The five 2D lattice types
- The 17 plane groups in 2D
Part 11: Symmetry in 3D Crystals
- Inversion, Roto-Inversion, and Roto-reflection
- Screw symmetry
Part 12: 3D Space Point groups
- Space point groups
- Stereographic projection
Part 13: 3D Space Groups
- Crystal lattices
- Space groups
Part 14: An Introduction to Tensors
- Symmetry constraints on materials properties
- Coordinate transformation
Part 15: Quasi, Plastic, and Liquid Crystals
- Quasi crystals
- An introduction to plastic and liquid crystals
- Liquid crystal descriptors
- Liquid crystal applications
Part 16: Introduction to Point Defects
- Thermodynamics of point defects
- Vacancies, interstitials, solid solutions and nonequilibrium defects
Part 17: Ionic Point Defects & Diffusion
- Kröger-Vink notation
- Extrinsic defects
- Diffusion
Part 18: Dislocations and Deformation
- Intro d shear stress
Part 19: Strengthening & Surface Energy
- Strengthening Mechanisms
- Surface free energy
- Wulff shape
Part 20: 2-Dimensional Defects
- Surface defects
- Stacking faults
- Grain boundaries
- Surface reconstruction
- Linear defects in liquid crystals
Les intervenants
Silvija Gradečak
Professor
Massachusetts Institute of Technology
Jessica Sandland
Lecturer & Digital Learning Scientist
Massachusetts Institute of Technology
Le concepteur
Le Massachusetts Institute of Technology (MIT), en français Institut de technologie du Massachusetts, est un institut de recherche américain et une université, spécialisé dans les domaines de la science et de la technologie. Situé à Cambridge, dans l'État du Massachusetts, à proximité immédiate de Boston, au nord-est des États-Unis, le MIT est souvent considéré comme une des meilleures universités mondiales.
Il édite la Technology Review, une revue scientifique consacrée aux sciences de l'ingénieur et à l'innovation.
La plateforme
EdX est une plateforme d'apprentissage en ligne (dite FLOT ou MOOC). Elle héberge et met gratuitement à disposition des cours en ligne de niveau universitaire à travers le monde entier. Elle mène également des recherches sur l'apprentissage en ligne et la façon dont les utilisateurs utilisent celle-ci. Elle est à but non lucratif et la plateforme utilise un logiciel open source.
EdX a été fondée par le Massachusetts Institute of Technology et par l'université Harvard en mai 2012. En 2014, environ 50 écoles, associations et organisations internationales offrent ou projettent d'offrir des cours sur EdX. En juillet 2014, elle avait plus de 2,5 millions d'utilisateurs suivant plus de 200 cours en ligne.
Les deux universités américaines qui financent la plateforme ont investi 60 millions USD dans son développement. La plateforme France Université Numérique utilise la technologie openedX, supportée par Google.
