1. METALS Properties, Processes and Types & Uses.

2. Introduction Among the 109 elements, 85 are classified as metallic, 7 as metalloids and 17 as nonmetallic. Metal Classification simple metals metallic alloys – purposeful mixture

3. Introduction

4. Metallic Properties Hardness Brittleness Malleability Ductility Elasticity Toughness Density Fusibility Conduction Contraction and Expansion Strength Corrosiveness

5. Introduction Crystallinity – degree of structural order of atoms in solids. Metals in gaseous and liquid state have no crystallinity.

6. Introduction ALLOYS – melting together of two metals to form a homogenous liquid.

7. Introduction Most of the industrially important alloys are based on 8 relatively cheap and abundant ones: IRON LEAD COPPER ZINC TIN NICKEL MAGNESIUM ALUMINUM

8. Treatment of Metals HOT AND COLD WORKING – deformation of metals or alloys in the cold as by rolling, stamping, swaging or drawing results in an increase in hardness and tensile strength and a decrease in ductility

9. Treatment of Metals HEAT TREATMENT– controlled heating and cooling of metals to alter their mechanical and physical properties without changing the product shape Purpose: Hardening Softening Material Modification

10. Treatment of Metals Hardening – increase in strength and wear Direct hardening Quench hardening Softening – reduce strength and hardness, restore ductility Annealing and recrystallization (50° C or 122°F) Normalizing (60°C or 140°F) Tempering (40°C or 104°F after quenching) Material modification– modify properties of materials Stress Relief

11. COMMERCIAL METALS STEEL IRON TITANIUM ALLOYS SUPERALLOYS ALUMINUM ALLOYS INTERMETALLIC COMPOUNDS

12. Ferrous Alloys - IRON Blast furnace Coke oven Limestone Iron ore Cast Iron Pig iron

13. Ferrous Alloys - Iron Cast iron - is roughly, the pouring of melted iron grades to patterns which would produce fine metal forms. Ordinarily, it is produced with Carbon to Iron ratio of more than 2% up to 4.5%. Cast Steel - is ordinarily, much lower in carbon than iron running from 0.2% to 0.35%

14. Ferrous Alloys - Steel STEEL - is primarily made from pig iron plus scrap melted into open-hearth furnace with flux and generally contains 0.05% to 2.0% Carbon. Plain Carbon Steels – iron and carbon steel Alloying Steels – with 5% non-carbon additions such as Mn, Cr, Ni, Cu, Si, Mo and V Stainless steel – more resistant to rusting due to Chromium addition (4%-30%) Tool steels – used for cutting, forming or shaping another material

15. Superalloys SUPERALLOYS - have been developed for high temperature service. Includes iron, cobalt and nickel-based materials A major application is in turbine materials, jet engines (both disc and blades)

16. Titanium Alloys TITANIUM - emerged as “wonder metal” in 1950 Relies on high strength/weight ratio, good resistance to corrosion, combined low thermal conductivity and thermal expansion Attractive for aerospace applications in both engine and airframe

17. Intermetallic Compounds are generally regarded as a class of materials between metals and ceramics Intrinsically strong with high elastic modulus Intermetallics containing Al or Si exhibit resistance to oxidation and corrosion Those made of light elements give rise to low density for weight-saving applications Greatest disadvantage is low ductility

18. Intermetallic Compounds Examples: Nickel Aluminides Titanium Aluminides Iron Aluminide Nickel Silicate PdIn Zirconium Aluminide

19. Aluminum Alloys ALUMINUM - has an attractive combination of properties such as low density, strong and easy to fabricate. Its two most important properties are density and thermal conductivity In engines, they are used as pistons, cylinder heads and sumps However, modulus of aluminum is only one third that of steel Super plastic forming is a cost-effective manufacturing process for producing both simple and complex shapes from aluminum alloy sheets