MTL 200 Chapter Notes - Chapter 1: Ionic Bonding, Covalent Bond, Burgers Vector

• School: Ryerson University
• Department: Mechanical Engineering
• Course: MTL 200
• Professor: Alan Mac Hin

Document Summary

Metals - sea of electrons, strong, ductile, high thermal and electrical conductivity, opaque, reflective. Ceramics - ionic bonding - metallic and nonmetallic elements (sulfides, nitrides, oxides), brittle, glassy, elastic, insulators (non conductors) Polymers/plastics - covalent bondings (sharing of electrons), soft ,ductile, low strength, low density, thermal and electrical insulators, translucent or transparent. Composites - two or more materials intentionally combined to produce new material with properties unattainable by other means. Semiconductors - covalently bonded, subclass of ceramics. Metals /alloys - steels, cast iron, magnesium, superalloys, aluminum, brass, copper, bronze. Ceramics - oxides, silicates, carbides, nitrides, chlorides, fluorites. Polymers - plastics, rubber, wood, wool, silk, leather. Materials selection process : application - determine required properties, properties - identify candidate material(s, material - identify required processing. Electrical: resistivity of copper - adding impurity atoms to cu increases resistivity, deforming cu increases resistivity. N=number of potential defect sites - density*(na/atomic weight)*volume. Qv=activation energy (ev/atom) k=boltzmann"s constant (either ev/atom-k or j/atom-k)