HSC Engineering Content Memorisation

5 Types of Corrosion

- Crevice- Galvanic- Pitting- Stress- Exfoliation

5 Corrosion Control Methods

- Sealants- Access for maintenance and inspection- Impressed current cathodic protection- Sacrificial anodes- Selection of appropriate metals - ones that develop protective oxide layer

5 Protective Coatings for Corrosion

- Grease and oil with inhibitors- Plasticised bitumen or resins- Rubber latex- Ceramic coatings (baked enamels)- Paints

2 Roles of Fibre in Fibre Reinforced Composites

- Supports or resists most of applied load- provides stiffness

4 Examples of Fibre Reinforced Composites

- Reinforced concrete- Prestressed concrete- Fibre reinforced polymers (FRP)- Fibre reinforced metals

3 Examples of Fibre Reinforced Polymers

- Graphite-epoxy- Graphite-kevlar-epoxy- Kevlar-epoxy

Example of Cermet

Tungsten-Carbide-Cobalt

Graphite-epoxy Usage

Used widely in aircraft and motor racing industry

Laminated Thermoset Plastic

Polymer impregnated into paper under pressure initiating polymerisation. Used for insulation and decorative surfaces

Five Alloys of Plain Carbon Steel

Low Carbon SteelMild SteelMedium Carbon SteelHigh Carbon SteelUltra-High Carbon Steel

Three Features Grey Cast Iron

- Graphite present as flakes- Stress concentrations occur at sharp ends- Graphite voids allow easy machining and damping properties

5 Crack Detection Tests

Dye Penetrant Inspection (DPI), Magnetic Particle Testing, Eddy Current Testing, Ultrasonic Testing, Radiography

Dye Penetrant Inspection (DPI)

Part is dipped in dye then washed away, developer is added leaving visible dye filled cracks - only for surface cracks

Magnetic Particle Testing

Fine magnetic particles are applied to surface. Part is magnetised to reveal surface and shallow defects because of stray EMF

Eddy Current Testing

Detects variation in an induced electromagnetic field

3 Advantages of Non-Ferrous Alloys

- Greater ductility- Lower density- Higher thermal and electrical conductivity

4 Properties of Aluminium Alloys

- Youngs modulus of 70 GPa compared to 210GPa for Steel- High electrical conductivity- Good corrosion resistance due to oxide layer- Low mass - used on high voltage power lines

2 Properties of Zinc Alloys

Low melting point and high corrosion resistance

3 Roles of Matrix in Fibre Reinforced Composites

- Adheres to fibre to transmit forces to fibres- Protects strands from damage- Prevents crack propagation

2 Types of Prestressed Concrete

Pre and Post Tensioned Concrete

3 Parts of the Composition of Concrete

- Aggregate - comprises 2/3 of the volume and must be angular- Sand - fills voids between aggregate minimising porosity, increasing cement life- Cement and water forms glue between sand and aggregate

Five Properties of Metals

- Lustrous- Solid at Room Temp- Malleable- Ductile- Good Conductors

3 Common Metal Structures

- Body Centered Cubic- Face Centered Cubic- Close Packed Hexagonal

Four Cast Irons

- Grey Cast Iron- Nodular/Spheroidal (SG) Graphite Cast Iron- White Cast Iron- Malleable Cast Iron

3 Conditions for Corrosion

- Presence of electrolyte like water- Presence of anode and cathode- An electrical contact between anode and cathode

2 Examples of Particle Reinforced Composites

- Cermet- Concrete

Tungsten-Carbide-Cobalt

Used for cutting tools - tungsten carbide particle cuts then fractures off the cobalt matrix to expose fresh sharp tungsten carbide

3 Examples of Laminates

- Plywood- Laminated Timber Beams- Laminated Thermoset Plastic

Four Properties of Non-Metals

- Dull- Brittle- Non-conductors- Cant Form Alloys

4 Properties of Ceramics

- Hard and brittle- High compressive low tensile strength- Low conductivity- Chemically inert

Three Steps of Grain Growth

1. Solidification into structure begins at nucleation points2. Grain dendrites grow (tree like)3. Grain boundaries form

Two Alloy Groups of Iron (C)

Steel - <2%Cast Iron - 2-4%

Eight Components of Alloy Steel

- Nickel- Chromium- Manganese and Silicon- Molybdenum- Tungsten- Vandium- Stainless Steels- High Speed Tool Steels

Silicon in Steel (%)

>1.5% used to aid formation of graphite

Four Annealing Processes

- Full Annealing- Process Annealing- Normalising- Spheroidising Annealing

5 Advantages of Aluminium Alloys

- Tensile strength up to 400MPa- Corrosion resistance- Weldability- Casting ability- Oxide non-toxic for food stuffs

3 Properties of Titanium Alloys

High specific strength, melting point and excellent corrosion resistance

Why Does Alloying Strengthen Materials

Disruptions in uniform atomic structure block slip planes

3 Points about Glass

- Glass is an amorphous solid - no regular crystalline structures - makes it transparent- Glass cannot be shaped by force - slip of atoms cannot occur- Very weak in tension - window will break on impact

4 Points about Cement

- Formed by complex reaction when aluminium oxide, soda and lime react at high temperatures- Strong in compression, weak in tension- Exhibits low toughness- Similar properties to stone with the advantage of casting

Points about Concrete

- Sand fills the gaps between the aggregate- Cement acts as the binder/matrix that hold the sand and aggregate together- The sand and aggregate bulk out the cerment, reducing the price and increasing strength

2 Points about Laminated Glass

- Used for shatter-resistance- Layers of glass are passed through roller that compress a polymer sheet between them