Revision 1: April 2011*

Revision 1: April 2011*Non-Ferrous MetalsThese are metals that contain no iron or a small amount of alloying iron, such as the alloys of aluminium, copper, magnesium, nickel, zinc and titanium.

Revision 1: April 2011*Copper - Properties Very ductile (can be easily worked) Corrosion resistant Good conductor of heat and electricity (second to silver) Easily joined by soldering, brazing and welding Relatively low strength (can be improved by alloying elements)

Revision 1: April 2011*Copper - ApplicationsCopper is used in the electrical industries/industries for making: (i) telephone wires, (ii) tubes for air conditioning and refrigeration applications, (iii) cables, (iv) busbars (v) lightning rods (vi) copper-alloy production http://en.wikipedia.org/wiki/Copper#Electronics_and_related_devicesBusbars

Revision 1: April 2011*Brass (Cu-Zn Alloys)Brasses include Cu-Zn alloys and the alloys that contain Cu-Zn-other alloy elementsIn this lecture, only Cu-Zn (up to 45%) is discussed.

Revision 1: April 2011*Phase Diagram For Cu-Zn Alloys Temperature (oC)

Revision 1: April 2011*Microstructures (Cu-Zn Alloys) phase: ductile solid solution; suitable for cold-working phase: ductile solid solution but less ductile than ; tougher than therefore suitable for hot working phase:metallic compound which is very brittle + :duplex structure

Revision 1: April 2011*Properties(Cu-Zn Alloys) contd Strength & elongation depend on the composition (i.e. % of zinc)- phase: generally tough & ductile; widely used in deep drawing- + : hard & brittle; lacks ductility so needs to be hot-worked.

Revision 1: April 2011*Properties (Cu-Zn Alloys) contdCastings are porous (poor quality)Strength can be improved by cold-working but cannot be improved by heat treatmentCorrosion resistant

Revision 1: April 2011*Mechanical Properties Of Cu-Zn Alloys+Elongation (%)U.T.S. (MPa)

Revision 1: April 2011*Applications(Cu-Zn Alloys) Tubes and rods Radiators Machine parts Electrical parts Heat exchangers Door knobs Brass locks

Revision 1: April 2011*Types Of Brasses And Their Applications

Copper Zinc Other Elements Applications (%) (%) (%)

Cartridge Brass 70 30 - Most ductile of the copper- zinc alloys. Widely used in sheet metal pressing for severe deep drawing operations. Originally developed for making cartridge cases hence its name. Standard Brass 65 35 - Cheaper than cartridge brass and less ductile. Suitable for most engineering purposes. Basic Brass 63 37 - The cheapest of the cold-working brasses. It lacks ductility and is only capable of withstanding simple forming operations.

Revision 1: April 2011*Types Of Brasses And Their Applications contd Copper Zinc Other Elements Applications (%) (%) (%)

Muntz Metal 60 40 - Not suitable for cold- working but hot-works well. Relatively cheap due to its high zinc content. It is widely used for extrusion and hot- stamping processes. Free Cutting Brass 58 39 3 (lead) Not suitable for cold-working but excellent for hot-working and high speed machining of low strength components. Admiralty Brass 70 29 1 (tin) This is virtually cartridge brass with a little tin to prevent corrosion in the presence of salt water.

Revision 1: April 2011*Types Of Brasses And Their Applications contd Copper Zinc Other Elements Applications (%) (%) (%)

Naval Brass 62 37 1 (tin) This is virtually Muntz metal plus a little tin to prevent corrosion in the presence of salt water.

Revision 1: April 2011*Tin Bronze(Cu-Tin Alloys)These are alloys of copper and tin together with a deoxidiser (e.g. phosphorus and zinc). The deoxidiser will prevent the tin content from oxidising during casting or hot-working.Oxidation of the tin will weaken the bronze Compare with brass, tin bronze is more expensiveStronger, more corrosion and wear resistanceMost of the tin bronzes contain up to 0.05% phosphorous which is the left-over from the deoxidation process that is carried out before casting. Sometimes, however, phosphorus (up to 1%) is deliberately added as an alloying element and only then should the material be termed as phosphor bronze.

Revision 1: April 2011*Phase Diagram Of Cu-Sn AlloysPart of copper-tin thermal equilibrium diagramTemperature (oC)520oC586oC + 798oC + + 10% TIN BRONZE

Revision 1: April 2011*Microstructures And Properties(Cu-Sn Alloys) Low tin bronze (3

Revision 1: April 2011*Microstructures And Properties(Cu-Sn Alloys) contdMedium tin bronze (10

Revision 1: April 2011*Microstructures And Properties(Cu-Sn Alloys) contdWhen zinc is added to the alloy for casting, it is called Gun Metal. The zinc will:(i)improve fluidity,(ii)reduce cost because it replaces some of the tin (Sn),(iii)give the alloy excellent pressure-tight, corrosion-resistant but it does not have the anti-friction properties of phosphor bronze,(iv)give advantage for large casting products such as hydraulic and steam valve body castings, castings for marine use.

Revision 1: April 2011*Microstructures And Properties(Cu-Sn Alloys) contd 13

Revision 1: April 2011*Applications Of Cu-Sn AlloysDrawn phosphor bronze is used in the work-hardened condition for turned components that require strength and corrosion resistance such as valve spindles;Cast phosphor bronze is usually cast into rods and tubes for making bearing bushes and worm wheels.

Revision 1: April 2011*Aluminium Properties And Applications Properties(i)Excellent resistance to normal atmospheric corrosion,(ii)Good thermal and electrical conductivity (second to copper),(iii)High malleability and ductility,(iv)Low strength and hardness(Strength of aluminium can be improved by adding alloying elements).

Revision 1: April 2011*Aluminium Properties And Applications contdApplications(i)Food-packaging (e.g. bottle caps, drink cans, packaging foil, trays, storage boxes, etc)(ii)Cooking utensils (e.g. kettles, sauce pans, etc)(iii)Electrical conductors - powerlines(iv)Indoor and outdoor furniture(v)Automobiles (e.g. wheel rims, carburettor housings, alternator housings, etc)(vi)Construction (e.g. pipes, sheets, tubing, tanks, bars, wire, windows, doors, rods, railings, ladders, shutters, etc) Note: Aluminium cannot be used as a structural material because of its low strength.

Revision 1: April 2011*Aluminium-Copper AlloysPart of phase diagram of Al-Cu alloys(Materials for Engineering Technician R.A. Higgins) + LIQUIDMOLTEN SOLUTION OF ALUMINIUM AND COPPER + COMPOUND (CuAl2)COMPOSITION OF DURALUMINTEMPERATURE548oC5.7%

Revision 1: April 2011*Microstructures And Properties(Al-Cu Alloys) contdEquilibrium cooling of duralumin (Al-4%Cu)

Structural changes taking place during heat treatment of Al-Cu alloy.(Materials for Engineering Technician R.A. Higgins)

Revision 1: April 2011*Microstructures And Properties(Al-Cu Alloys) contdEquilibrium cooling (slow) of duralumin (Al-4%Cu)(i)T = T1, phase is in un-saturated state.(ii)T < T2, phase remains in saturated state with some precipitation occurring.T = T3 (room temp.), phase + coarse precipitate phase (CuAl2)Properties: At temperature, T3, alloy is soft and has low tensile strength.

Revision 1: April 2011*Microstructures And Properties(Al-Cu Alloys) contdAge Hardening-Involves two steps (i)solution treatment (ii) ageing. This is a special dispersion strengthening heat treatment.-In age hardening, a coherent precipitate form will provide a substantial strengthening effect.

Age hardening and precipitation hardening

Revision 1: April 2011*Microstructures And Properties(Al-Cu Alloys) contd Solution Treatment - Alloy is heated to a temperature above the solvus temperature (T2 in phase diagram) and held until a homogeneous solid solution () is produced.-Alloy is quenched (fast cooling) from temperature T1 phase is supersaturated and precipitation is prevented.at room temperature, structure is supersaturated crystals. Properties higher tensile strength than slow- cooled (solid solution strengthening) ones but still ductile.

Revision 1: April 2011*Microstructures And Properties(Al-Cu Alloys) contdAgeing- Two types (i) natural ageing (ii) artificial ageing- Natural ageing Precipitation occurs at room temperature for a relatively long period of time.- Artificial ageing Precipitation is sped up by heating to a higher temperature but below the solvus temperature (T2) for a relatively short time.

Revision 1: April 2011*Microstructures And Properties(Al-Cu Alloys) contdSolution Treatment and Ageing will result in:Precipitation in the form of fine particles of CuAl2 which is hard and brittle.Increase in tensile strength and hardness.Increase in possibility of cracking during cold-working.

Revision 1: April 2011*Effect Of Temperature and TimeOn The Strength Of Al-Cu AlloysAgeing Temperature-As temperature decreases, longer time is needed to obtain maximum strength.Ageing Time-The tensile strength will increase with ageing time to a maximum value (coherent precipitate) and then decrease with increase in time (over-age result from non-coherent precipitate).

Revision 1: April 2011*Effects Of Temperature And Time On Strength Of Al-Cu Alloys(160oC, 10 hours)(Materials for the Engineering Technician R.A. Higgins)

Revision 1: April 2011*Applications Of Al-Cu AlloysAl-Cu alloys are used as follows:(i)In aircraft, as stressed parts and other structures.(ii)Engine parts such as connecting rods, etc.(iii)Military equipment requiring high strength-to-weight ratio

Revision 1: April 2011*Aluminium-Silicon Alloys (Al-Si)Note:Addition of silicon to Al will increase fluidity during casting and reduces shrinkage.Unmodified and modified Al-Si phase diagrams

Revision 1: April 2011*Microstructures And Properties(Al-Si Alloys) Unmodified structuresEutectic alloy: phase + Si (coarse eutectic structure)Hyper-eutectic alloy: coarse eutectic structure + coarse Si crystals.Properties: poor mechanical properties as well as brittle.

Revision 1: April 2011*Microstructures And Properties(Al-Si Alloys) contdModified structuresModification by adding 0.005% 0.15% sodium (Na) to Al-Si alloy before casting.Structures consist of primary + fine eutectic structure (fine grains)Na will cause Si to nucleate but prevents its growth. The structure will therefore be a solid solution in a fine eutectic matrix.Properties: higher strength, better ductility (fine grain size) and corrosion resistance

Revision 1: April 2011*Microstructures And Properties(Al-Si alloys) contdEffects of modification(i)Raises eutectic composition and decreases eutectic temperature(E.g. modified Al-13%Si alloy becomes a hypoeutectic alloy).(ii)Lower melting temperature (Tm)and freezing range, lower shrinkage and therefore very suitable for die casting (lower Tm will improve fluidity).

Revision 1: April 2011*Applications Of Al-Si AlloysAl-Si alloys are used for the following:(i)Radiators(ii)Sumps(iii)Gear boxes

Revision 1: April 2011*Titanium-Based Alloys(Properties And Applications)Properties(i) High strength (even at high temperature)(ii) High corrosion resistance(iii) High specific strength (strength/weight ratio)(iv) High melting point (about 1668oC)Applications (i)Jet engines(ii) Aircraft and spacecraft parts(iii) Heat exchangers(iv) Condensers (in power plants and refineries)

Revision 1: April 2011*Magnesium-Based Alloys(Properties And Applications) Properties(i)Lower relative density(ii)Strength can be improved by precipitation- hardening treatments. Applications(i)Castings and forging in the aircraft and automobile industriesLanding wheelsPetrol tanksOil tanksEngine parts piston and jet enginesGearbox casings of racing cars

Revision 1: April 2011*

*STOP ON 17TH SEPT 2003Stopped on 14th July 2011.**STOPPED 1P01/1P02 (14th March 02)