A Level Design and Technology AQA

Materials and Their Applications

Materials and Their Applications

Understanding Materials

• Different materials have diverse characteristics and qualities, which determine their use in particular applications.
• Understanding the characteristics, properties and behaviour of materials helps in effective selection.
• Knowledge about the processing and modification of materials (both physical and chemical), their operational parameters, and factors that facilitate or restrict their use, is crucial.
• Equally important is understanding the environmental impact of using different materials, including recyclability.

Classes of Materials

Ferrous and Non-Ferrous Metals

• Ferrous metals, like iron and steel, are characterised by their strength, hardness, and their conductive properties but are susceptible to rust.
• Non-ferrous metals, such as aluminium, copper or brass, are more resistant to corrosion, but they may be less strong. They're often used for their good thermal and electrical conductivity.

Ceramics

• Ceramics are hard, strong but brittle, and often good insulators. They have uses ranging from kitchenware to electronics to bio-medical applications.

Polymers

• Polymers, or plastics, have large variety and wide range of properties, including flexibility, durability and resistance to chemicals and electricity.

Composites

• Composites consist of two or more constituent materials, designed to have properties superior to those of the individual components.

Smart Materials

• Smart Materials respond to changes in their environment (such as temperature or light) and have a range of advanced and specialised uses.

Properties and Performance of Materials

• Mechanical properties of materials include strength, hardness, ductility, and toughness.
• Physical properties to consider include density, electrical and thermal conductivity, and melting point.
• The environmental impact of materials is gauged considering the life-cycle analysis (including energy use, emissions and waste disposal) and the potential for recycling.

Material Selection and Use

• The selection of materials for a given application must be linked to the desired properties and characteristics, the manufacturing processes available, and the environmental footprint.
• Understanding the impact of processes and conditions on material properties is crucial, including annealing, work hardening, heat treatment, and tempering.
• Knowledge of joining techniques such as welding, brazing, riveting, and using adhesives, is essential.

Understanding Mechanical Systems

• Understanding how material selection impacts on mechanical systems is crucial. Key considerations include understanding the impact on friction, lubrication, and wear and tear.
• Materials should also be evaluated in the context of forces (including tension, compression, torsion and shear), the behaviour of beams, shafts and columns and effects like buckling.

Material Testing

• Material testing involves finding key properties and behaviours under a set of conditions. This might include studying the effect of load, temperature, corrosion, and so on.
• It's crucial to understand the significance of test results and their correlation with the appropriate use of materials.

Always remember, knowledge of materials and their applications forms the foundation for design thinking and technological advancement.