Lecture 1 There are four main material groups: Metals Polymers Ceramics Composites and natural materials Materials from the same family with have similar properties to others in the same family. Each family will have two sub-families. Polymers: Thermoplastics Thermoset plastics Ceramics Structural ceramics Electrical ceramics Metals Ferrous metals Nonferrous metals Composites and naturals materials man-made materials natural materials Each material property has a quantitative value related to it; this allows material behavior to be compared easily. Material properties: Mechanical properties Chemical properties Physical properties Composites and natural material properties The material properties of composites can vary considerably depending on the nature of the material and manufacturing Lecture 1 Material properties and characteristics Density- Mass per unit volume kg/m³ Thermal conductivity- The ability of a material the absorb heat Electrical conductivity- The ability of a material to transfer electrical current Melting point- The temperature at which a solid material changes to liquid Hardness- The ability for a material to resist indentation (resistance to wear) Flexural/ young’s modulus- ease of bending the material Tensile strength- the ability of a material to resist tension Toughness- ability of a material to absorb energy and plasticly deform without fracturing. Lustre- Shiny appearance Structure- Materials with the same structure will tend to have similar physical properties Opaqueness- The materials ability to permit light to pass through it Expansion and contraction- A materials ability to change in size due to a change in temperature Magnetism- An object that is surrounded by a magnetic field and that has the property, either natural or induced, of attracting iron. Ductility- A materials ability to be plasticly deformed without fracturing Malleability- A materials ability to be shaped, hammered and rolled without rupturing.