B-06A - Aircraft Materials and Corrosion

• Ferrous metals


  Metals containing iron
• Iron (Ferrite)


  • The basic element in ferrous metals
• Steel


  An alloy of iron and carbon
• Alloying agents in steel

  Elements added to steel to modify its properties
• Carbon


  The primary alloying agent in steel
• Other alloying agents in steel

  • Chromium
  • Nickel
  • Manganese
  • Molybdenum
  • Vanadium
• Stainless steel


  Steel alloy with high corrosion resistance
• Heat treatment of steel

  1. Annealing

  2. Normalising

  3. Hardening

  4. Tempering

  5. Case hardening
• Purpose of steel heat treatment

  To modify the mechanical properties of steel
• Non-ferrous metals


  • Metals that do not contain iron
• Aluminium alloys


  Aluminium combined with other metals to improve properties
• Clad aluminium alloy (Alclad)

  Aluminium alloy with a pure aluminium surface layer
• Heat treatment of aluminium alloys

  1. Solution heat treatment

  2. Precipitation heat treatment

  3. Annealing
• Aluminium alloy temper designations


  Indicate the mechanical properties of the alloy
• Non-heat-treatable aluminium alloys are strengthened by strain-hardening
• Other non-ferrous alloy types

  • Magnesium
  • Titanium
  • Nickel
  • Copper
• Hardness testing


  Brinell and Rockwell hardness tests
• Tensile strength testing


  Measures a material's resistance to being pulled apart
• Fatigue strength testing


  Measures a material's resistance to cyclic loading
• Impact resistance testing


  Measures a material's resistance to sudden impact or shock
• Composite structure


  Made from two or more materials with different properties
• Composite reinforcing fibres


  • Fibreglass
  • Aramid
  • Carbon
  • Ceramic
• Composite matrix systems


  Resin materials that bind the reinforcing fibres together
• Composite matrix resin types

  • Epoxy
  • Polyester
  • Vinyl ester
  • Phenolic
• Composite adhesives


  Bonding agents used to join composite parts
• Pre-impregnated composite materials


  Reinforcing fibres pre-coated with resin
• Composite inspection methods


  • Visual
  • Tap testing
  • Ultrasonic
  • Radiographic
  • Thermography
• Composite defects and damage

  • Cosmetic defects
  • Impact damage
  • Delamination
  • Disbonds
  • Cracks
  • Resin matrix damage
  • Water/fluid intrusion
  • Hole damage
• Composite repair process


  1. Damage assessment

  2. Potted repairs

  3. Injection repairs

  4. Laminate repairs

  5. Sandwich structure repairs

  6. Honeycomb core repairs

  7. Transparent plastic repair
• Corrosion


  Deterioration of a material due to chemical or electrochemical reactions
• Types of corrosion


  • Galvanic
  • Stress
  • Surface
  • Pitting
  • Intergranular
  • Filiform
  • Fretting
  • Exfoliation
  • Microbiological
• Metal susceptibility to corrosion

  • Aluminium
  • Magnesium
  • Titanium
  • Cadmium
  • Chromium
  • Nickel
  • Copper
  • Silver
  • Gold
  • Tin
• Rivets


  Fasteners used to join aircraft structures
• Rivet alloy types


  • 1100 aluminium
  • 2117 aluminium alloy
  • 5056 aluminium alloy
  • 2017 aluminium alloy
  • 2024 aluminium alloy
  • 7050-T73 aluminium alloy
  • Corrosion-resistant steel
  • Monel
• Special rivets and fasteners

  Blind rivets, friction-lock rivets, mechanical-lock rivets, Hi-Shear rivets, Hi-Loks, Jo-Bolt
• Rigid fluid lines


  Metal tubing used to transport fluids in aircraft
• Rigid line fittings and unions

  • Flared-tube fittings
  • Flareless tube fittings
  • Universal bulkhead fittings
  • Tapered pipe thread fittings
  • Banjo fittings
  • Quick-disconnect couplings
• Flexible fluid lines


  Hoses used to transport fluids in aircraft
• Flexible hose types


  • Braided hose
  • Convoluted hose
  • Teflon hose
• Flexible hose fittings


  Swaged-end fittings, reusable fittings