Materials Part 1: Properties of wood and metals Chapter 1 Materials Part 1: Properties of wood and metals

Materials part 1 Learning Objectives By the end of this lesson you will have developed a knowledge and understanding of: what each of the properties of a material means the working characteristics of common forms of materials how these materials are made and what happens to them at the end of the usable life of the product the differences between softwood and hardwood and between natural timber and manufactured boards the difference between ferrous and non-ferrous metals how the properties of metals can be changed by heat treatment. AQA GCSE Design and Technology: resistant materials technology

Material properties Mechanical properties are about how the material reacts when a force is applied to it. Physical properties are characteristics of the material which are not affected by applying a force to it. AQA GCSE Design and Technology: resistant materials technology

Mechanical properties Strength: tensile compressive shear torsion bending Hardness Elasticity Flexibility Malleability AQA GCSE Design and Technology: resistant materials technology

Physical properties Corrosion resistance Thermal conductivity Electrical conductivity Density Strength-to-weight ratio Aesthetic qualities Sustainability Cost AQA GCSE Design and Technology: resistant materials technology

Classes of material Groupings based on what they are made from: wood metal polymers (plastics) ceramics composites Groupings based on the material properties: smart materials AQA GCSE Design and Technology: resistant materials technology

Wood – hardwood From deciduous trees that lose their leaves in winter: beech ash elm oak mahogany teak. AQA GCSE Design and Technology: resistant materials technology

Wood – softwood From coniferous trees that stay green all year round: redwood western red cedar parana pine whitewood. AQA GCSE Design and Technology: resistant materials technology

Market forms of wood Standard timber sizes Typical planed timber sizes AQA GCSE Design and Technology: resistant materials technology

Market forms of wood Timber mouldings AQA GCSE Design and Technology: resistant materials technology

Types of manufactured board AQA GCSE Design and Technology: resistant materials technology

Metals Ferrous metals which contain iron: cast iron steel stainless steel. Non-ferrous metals which do not contain iron: aluminium copper brass. AQA GCSE Design and Technology: resistant materials technology

Market forms of metal AQA GCSE Design and Technology: resistant materials technology

Heat treatment Heat treatment can be used to change the properties of metals: Quenching and tempering: Hardens and toughens high carbon steels. Case hardening: Hardens the surface of low carbon steel. Normalising: Makes work hardened steel tough and ductile. Annealing: Makes work hardened metals softer and easier to work. AQA GCSE Design and Technology: resistant materials technology

Heat treatment Structure of steel at different temperatures AQA GCSE Design and Technology: resistant materials technology