1-Materials and their applications

• Different materials work in different ways, and designers and manufacturers must know about material properties to make sure the product is a success
• Selecting the best material will be a compromise of factors such as aesthetics, cost and manufacturing method, as well as reuse but the final choice is mostly influenced by product function and the materials properties
• Mechanical properties


  Properties associated with how a material reacts to an external force
• Compressive strength


  • The ability to withstand being crushed or shortened by pushing forces (compression)
• Tensile strength


  • The ability to resist stretching or pulling forces (tension)
• Bending strength


  • The ability to resist forces that may bend the material
• Shear strength


  • The ability to resist sliding forces on a parallel plane
• Torsional strength


  • The ability to withstand twisting forces from applied torque or torsion
• Hardness


  • The ability to resist abrasive wear such as scratching, surface indentation or cutting
• Toughness


  • The ability to absorb impact force without fracture
• Plasticity


  • The ability to be permanently deformed and retain the deformed shape
• Ductility


  • The ability to be drawn out under tension, reducing the cross-sectional area without cracking
• Malleability


  • The ability to withstand deformation by compression without cracking, malleability increases with a rise in temperature
• Elasticity


  • The ability to be deformed and then return to the original shape when the force is removed
• Physical properties


  Properties associated with the actual make-up or structure of the material
• Density


  • The mass of the material in a standard volume of space
• Fusibility


  • The ability of the material to be fused or converted from a solid to a liquid or molten state, usually by heat
• Magnetism


  • The natural force between objects that causes the material to attract iron or steel
• Corrosion/degradation resistance


  • The ability of the material to withstand environmental attack and decay
• Electrical conductor


  Allows the flow of electrical current through the material, giving very little resistance to the flow of charge
• Electrical insulator


  Does not allow the flow of electricity through the material
• Thermal conductor


  Allows the transfer of heat energy through the material, allowing the transfer of heat to occur quickly across the material
• Thermal insulator


  Prevents the transfer of heat through the material
• Thermal expansion


  The increase in material volume in response to a heat input
• Opaque


  Prevents light from traveling through
• Translucent


  Allows light through but diffuses the light so that objects appear blurred
• Transparent


  Allows light to pass through easily, which means you can see clearly through the material