Metals can be classified as metallic, metalloids, or nonmetallic. Metallic properties include hardness, brittleness, malleability, ductility, elasticity, toughness, density, fusibility, conduction, contraction, expansion, and strength. Alloys are formed by melting two metals together. The most important industrial alloys are based on iron, lead, copper, zinc, tin, nickel, magnesium, and aluminum. Metals can be treated through hot/cold working and heat treatment to modify properties without changing shape. Common commercial metals include steel, iron, titanium alloys, superalloys, aluminum alloys, and intermetallic compounds.

1. METALSProperties, Processes and Types & Uses.

2. IntroductionAmong the 109 elements, 85 are classified as metallic, 7 as metalloids and 17 as nonmetallic. Metal Classificationsimple metalsmetallic alloys – purposeful mixture

3. Introduction

4. Metallic PropertiesHardnessBrittlenessMalleabilityDuctilityElasticityToughnessDensityFusibilityConductionContraction and ExpansionStrengthCorrosiveness

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

6. IntroductionALLOYS – 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:IRONLEADCOPPERZINCTINNICKELMAGNESIUMALUMINUM

8. Treatment of MetalsHOT 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 MetalsHEAT TREATMENT– controlled heating and cooling of metals to alter their mechanical and physical properties without changing the product shape Purpose:Hardening SofteningMaterial Modification

10. Treatment of MetalsHardening – increase in strength and wearDirect hardeningQuench hardeningSoftening – reduce strength and hardness, restore ductilityAnnealing 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 materialsStress Relief

11. COMMERCIAL METALSSTEELIRONTITANIUM ALLOYSSUPERALLOYSALUMINUM ALLOYSINTERMETALLIC COMPOUNDS

12. Ferrous Alloys - IRONBlast furnaceCoke ovenLimestoneIron oreCast IronPig iron

13. Ferrous Alloys - IronCast 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 steelAlloying Steels – with 5% non-carbon additions such as Mn, Cr, Ni, Cu, Si, Mo and VStainless steel – more resistant to rusting due to Chromium addition (4%-30%)Tool steels – used for cutting, forming or shaping another material

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

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

17. Intermetallic Compoundsare generally regarded as a class of materials between metals and ceramicsIntrinsically strong with high elastic modulusIntermetallics containing Al or Si exhibit resistance to oxidation and corrosionThose made of light elements give rise to low density for weight-saving applicationsGreatest disadvantage is low ductility

18. Intermetallic CompoundsExamples:Nickel AluminidesTitanium AluminidesIron AluminideNickel SilicatePdInZirconium Aluminide

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