8.2 - Material Classification Flashcards
Types of Engineering materials?
Metals (1-3 valance electrons)
Non-metals (4-8)
Types of metals?
Ferrous (contain iron)
Non-ferrous metals
Types of Ferrous metals?
Wrought Iron (<0.008% carbon) Steels (alloy of iron, carbon, and possibly more) Cast Irons (>2% carbon)
Types of Steels?
Alloy Steels (iron, carbon, and more) Plain carbon steels (iron and carbon)
Types of Non-metals?
Synthetic materials / Plastics (man-made, consist of wide range of carbon based compounds with molecules of high molecular mass) Natural materials (from plants, animals, ground)
Examples of Natural materials?
Rubber Glass Wood Ceramics Diamond Oil
Types of Synthetic materials?
Thermoplastics (heated, do not undergo chemical change, can be moulded) Thermosetting plastics (heated, melt and take shape only once, irreversible chemical reaction)
Classes of materials?
Metals
Polymers
Ceramics
Composites
Metal qualities?
Hard Opaque Good heat / electrical conductors Shiny Malleable (can be pressed perm. without braking) Ductile (drawn into thin wire)
Metal examples?
Steel
Copper
Aluminium
What’s an alloy?
Mixture of a metal and other elements, made for unique qualities
What is heat treatment?
A metal, like hard steel, is heated and rapidly cooled in oil or water (quenching) to strengthen it
Polymer qualities?
Consist of large molecules, composed of many repeating sub-units (joined by polymerisation)
Malleable (can be moulded)
Polymer examples?
PVC (polyvinyl chloride)
PTFE (polytetrafluoroethylene), eg. Teflon
What’s an elastomer?
Rubbers that can be stretched, have large elastic strains, eg. car tyres and elastic bands
Ceramic qualities?
Hard Brittle (tension and compression) Good insulators Good chemical resistance High melting temps (formed whilst in powder form, with water and heat)
Ceramic composition?
Chemical compound formed of oxides such as silica (sand), sodium and calcium, as well as silicates (eg. clay)
Ceramic examples?
Glass (contains silica)
Brick / clay
Kaonlinite (traditional raw ceramic)
Alumina / ali oxide (new raw)
Composite composition?
Made from two or more constituent materials with significantly different physical / chemical properties, the individual components remain separate and distinct in the finished structure
Alloy examples?
Brass - copper and zinc
Stainless steel - iron, carbon, nickel and chromium
Composite examples?
Reinforced concrete is made from steel and concrete (steel good for tension, concrete good for compressive loads)
Fibre reinforcement of a resin matrix (light, stiff, strong and tough)
Bones
