DMT.07 Metals & Alloys

DMT.07 Metals & Alloys

1. Keywords

   • Grain - Crystalline structure
   • Grain Boundary - Junction of adjacent grains

2. Uses

   • Denture Framework
   • Crowns/Bridges/Inlays
   • Wires
   • Instruments
   • Direct filling - Amalgum

3. Characteristics

   • HArd / Shiny
   • Dense
   • Conduct - Heat/ Elctricity

4. Melting & Crystallisation

   • Melting & solidification are reversible

5. Crystal Growth

   • Dendrites Shape
     • Equiaxed Structure

6. Nuclei

   • Seeding - encourage more grains

7. Grain Boundary

   • Barrier to movement

8. Shaping of Metals and Alloys

   • Casting
     • Melt Metal
       • Pour liquid metal into a mould
   • Cold Working
     • Plastic deformation of metals
       • Squeezing , bending, shearing
   • Amalgamation
     • Reaction with mercury
       • Moulding of paste

9. Atomic Arrangement

   • Regular arrangement of atoms
   • Long- Range Order
   • Crystaline

10. Crystal Structure

    • Simple Cubic
      • Ionic Compounds
    • Body centred Cubic
      • Metals
    • Face centred cubic

11. Crystal Defects

    • Point Defects
    • Line Defects