上海交通大学：《材料导论》教学资源（英文）Relationship between structure and properties

Relationship between structure and properties 上游克大学

Relationship between structure and properties

Materials can move

Materials can move

Factors affecting materi properties Crystal structure Grain size Bonding Structure Defects Composites Adding elements

Factors affecting material properties Bonding Structure Crystal structure Defects Grain size Composites Adding elements

Structure on different scale Subatomic level Electronic structure of individual atoms that defines interaction among atoms (interatomic bonding). Atomic leve Arrangement of atoms in materials (for the same atoms can have different properties,e.g.two forms of carbon:graphite and diamond) Microscopic structure Arrangement of small grains of material that can be identified by microscopy. Macroscopic structure Structural elements that may be viewed with the naked eye. Mona ch butterfly

Structure on different scale • Subatomic level Electronic structure of individual atoms that defines interaction among atoms (interatomic bonding). • Atomic level Arrangement of atoms in materials (for the same atoms can have different properties, e.g. two forms of carbon: graphite and diamond) • Microscopic structure Arrangement of small grains of material that can be identified by microscopy. • Macroscopic structure Structural elements that may be viewed with the naked eye. Monarch butterfly

Properties Metals:strength,ductility,high melting point, thermal and electrical conductivity,and toughness. Ceramics:hard and brittle,insulators,optically opaque,semi-transparent,or transparent,heat and corrosion resistant,less dense than metals, refractory *Semiconductors:conductivity between conductors and insulators Polymers:light weight,insulator,anti-corrosion, low melting point

Properties Metals : strength, ductility, high melting point, thermal and electrical conductivity, and toughness. Ceramics: hard and brittle, insulators, optically opaque, semi-transparent, or transparent, heat and corrosion resistant, less dense than metals, refractory Semiconductors: conductivity between conductors and insulators Polymers: light weight, insulator, anti-corrosion, low melting point

Let's start from the subatomic level

Let’s start from the subatomic level……

Metallic Bonding e e e -Metal "kernel"e -Electron cloud *Strong Coulomb Force:high melting point,strength,hardness *Electrons can move freely:electrical and thermal conduction, ductility Showing no difference in different direction:isotropy (anisotropy)

Metallic Bonding e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e - Metal "kernel" - Electron cloud e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e  Strong Coulomb Force: high melting point, strength, hardness  Electrons can move freely: electrical and thermal conduction, ductility  Showing no difference in different direction: isotropy (anisotropy)

Ionic bonding 库仑键力 *Electrons are transferred *Large difference in electronegetivities *strong and non-directional:high melting point,hard but brittle,insulator

Ionic bonding  Electrons are transferred  Large difference in electronegetivities  strong and non-directional: high melting point, hard but brittle, insulator

Covalent bonding (蓝色小球代表电子) *Electrons are not transferred but shared *small electronegativity differences *Strong and directional:high melting point,hard,brittle, insulator

Covalent bonding  Electrons are not transferred but shared  small electronegativity differences  Strong and directional: high melting point, hard, brittle, insulator

Thermal properties determined by bonding 100 50 0 -50 Empirical Lennard-Jones e时转时it -100 3.0 4.0 5.0 6.0 7.0 8.0 R (A)

Thermal properties determined by bonding