文档介绍：材料科学基础 Fundamental of Materials
Prof: Tian Min Bo
Tel: 62795426 ,62772851
E-mail: ******@.
Department of Material Science and Engineering
Tsinghua University. Beijing 100084
§ Space Lattice
Ⅰ.Crystals versus non-crystals
1. Classification of functional materials
Chapter Ⅱ
Fundamentals of Crystallography
Lesson three
2. Classification of materials based on structure
Regularity in atom arrangement
—— periodic or not (amorphous)
Crystalline: The materials atoms are arranged in a periodic fashion.
Amorphous: The material’s atoms do not have a long-range order (~1nm).
Single crystal: in the form of one crystal
grains
Polycrystalline:
grain boundaries
Ⅱ.Space lattice
1. Definition:
Space lattice consists of an array of regularly arranged geometrical points, called lattice points. The (periodic) arrangement of these points describes the regularity of the arrangement of atoms in crystals.
2. Two basic features of lattice points
Periodicity: Arranged in a periodic pattern.
Identity: The surroundings of each point in
the lattice are identical.
A lattice may be one , two, or three dimensional
two dimensions
Space lattice is a point array which represents the regularity of atom arrangements
(1) (2) (3)
a
b