engineering materials

• What is the main consideration when choosing a material for an application?

  Match application properties to material properties
• What is tensile strength?

  Resistance to pulling forces
• What are the two values often given for tensile strength?

  Yield strength and ultimate tensile strength
• What does yield strength indicate?

  Stress needed for permanent deformation
• What is ultimate tensile strength (UTS)?

  Stress at which material breaks
• What is compressive strength?

  Resistance to squeezing forces
• How do most metals perform in terms of strength?

  Good strength against various forces
• What is the definition of strength in materials?

  Ability to resist a force
• What is ductility?

  Ability to be stretched without breaking
• How is ductility measured?

  Ratio of extended length to original length
• What is malleability?

  Ability to change shape without breaking
• What does hardness refer to in materials?

  Resistance to marking or cutting
• What is the difference between toughness and brittleness?

  Toughness withstands impact; brittleness shatters
• What is stiffness?

  Resistance to bending
• How is stiffness measured?

  By calculating Young's Modulus
• What affects the stiffness of a material?

  The shape of the material
• What are the two main types of metals?

  Ferrous and non-ferrous
• What is corrosion?

  Gradual destruction of metal by chemical reaction
• What is work hardening?

  Increase in strength due to cold working
• What is annealing?

  Heat treatment that softens metal
• What is quenching?

  Rapid cooling of hot metal in liquid
• What is tempering?

  Heat treatment to reduce brittleness
• What is carburising?

  Addition of carbon to improve hardness
• What is the purpose of case hardening?

  To produce a hard skin that resists wear
• What is the effect of corrosion on steel?

  It eats away the material and affects appearance
• What are the standard forms of metals?

  Flat strip, round bar, square bar, etc.
• What is a non-ferrous metal?

  A metal that does not contain iron
• Why is steel considered an alloy?

  It is a mixture of metals
• Name two ferrous metals.

  Cast iron and low-carbon steel
• Name two non-ferrous metals.

  Copper and aluminium
• What is the typical use of aluminium?

  Cooking utensils and aircraft bodies
• What are thermoplastics?

  Polymers that can be reshaped when heated
• How do thermoplastics behave when heated?

  They become softer and flexible
• What is a common property of thermoplastics?

  They can be recycled by melting
• What is a thermosetting polymer?

  A polymer that cannot be reshaped when heated
• What is the typical use of nylon?

  Gear wheels and bearings
• What is the property of polycarbonate?

  High strength and toughness
• What is the typical use of polystyrene?

  Packaging and foam cups
• What is the property of acrylic?

  Good optical properties and transparency
• What is the typical use of high impact polystyrene (HIPS)?

  Good for vacuum forming and packaging