Nonferrous Alloys PDF

NONFERROUS METALS AND ALLOYS Aluminum, Copper, Magnesium, Titanium, Nickel and Its Alloys 1  NONFERROUS METALS  Ferrous metals have some limitations, chiefly:  a relatively high density,  a comparatively low electric...

NONFERROUS METALS AND ALLOYS Aluminum, Copper, Magnesium, Titanium, Nickel and Its Alloys 1  NONFERROUS METALS  Ferrous metals have some limitations, chiefly:  a relatively high density,  a comparatively low electrical conductivity, and  an inherent susceptibility to corrosion in some common environments.  Although ferrous alloys are specified for more engineering applications, large family of nonferrous metals offers a wider variety of properties. For example: The lightest metal is lithium, 0.53 g/cm3 (but it is not a structural metal. The lightest structural metal is Mg, 1,7 g/cm3). The heaviest metal is osmium, 22,5 g/cm3. Mercury melts at -400C, while tungsten liquefies at 34100C. 2  NONFERROUS METALS  Nonferrous metals have numerous applications because of such properties: low density, high thermal and electrical conductivity good corrosion resistance ease of fabrication. But nonferrous alloys more expensive than steels and plastics. 1) High stregth nonferrous alloys: aluminium, copper and magnesium 2) High temperature nonferrous metals: tungsten, tantalum, molybdenum. Typical examples of nonferrous metal and alloy applications are Aluminium for cooking utensils and aircraft bodies, Copper wire for electrical power cords, Zinc for galvanized sheet metal for car bodies Titanium for jet-engine turbine blades and orthopedic implants Tantalum for rocket engine components. 3  ALUMINUM and its alloys  Aluminum currently is probably the most important of the nonferrous metals.  Aluminum has light weight (2.7 g/cm3 as compared to 7.9 g/cm3 for steel), high strength-to-weight ratio, high thermal and electrical conductivities, corrosion resistance in some common environments, including the ambient atmosphere, good ductility even at low temperaturesand ease of weldability. However, its melting temperature is low (6600C).  It is suitable for casting, all machining and forming operations. 4  It has low strength (90 MPa), but the mechanical strength of Al may be enhanced by cold working and by alloying, but processes tend to diminish resistance to corrosion.  The principal alloying elements for Al are Cu, Mg, Si, Mn, and Zn.  Aluminum alloys number hundreds, such as 2024, 7075, 6061 and so on. These are Aluminum Association Numbers (AAN). Applications In its structural (load-bearing) components, 82% of a Boeing 747 aircraft and 70% of a 777 aircraft is aluminium. The Boeing 787 Dreamliner (first placed into service in late 2012) is well recognized for its carbon-fiber reinforced composite fuselage, although it still uses 20% aluminium by weight, as compared to 15% titanium. The frame and the body panels of the Rolls Royce Phantom coupe are made of aluminium, improving the car’s strength-to-weight. In containers and packaging (aluminium beverage cans and foil) Nearly all high voltage transmission wiring is made of aluminium. 5 6 7   Al alloys are classified as either cast or wrought. Al alloys Wrought alloys (shaped by plastic deformation) Cast alloys: (Designation: 1XX.X-9XX.X) (Designation: 1XXX-9XXX) Last digit indicates product form. 0 is for casting. 1 or 2 is ingot (depend upon purity) Heat-treatable Nonheat-treatable Heat-treatable Nonheat-treatable 2024-T4: 1100-0 356.0-T6*** 443.0-F*** 4.4 Cu, 1.5 Mg, 0.6 Mn. >99%Al, elongation: 45% 7.0 Si, 0.3 Mg. 5.2 Si, elongation: 20%, Tensile strength: 470 MPa Tensile strength: 90 MPa elongation: 3% elongation: 8% Aircraft structures, rivets, truck wheels. Food/chemical handing and storage Tensile strength: 228 MPa equipment, heat exchangers 6061-T6 5052-H32 *** 1.0 Mg, 0.6 Si, 0,3 Cu, 0,2 Cr. 2.5 Mg, 0.25 Cr elongation: 17%, Tensile strength: 310 MPa elongation: 18% Trucks, furniture, pipelines Tensile strength: 230 Mpa Bus,truck, and marine uses. 7075-T6: 5.6 Zn, 2.5 Mg, 1.6 Cu, 0.23 Cr. elongation: 11%, Tensile strength: 570 MPa Aircraft structures and other high stressed applications.  2024 and 7075 are as strong as 1040 steel. Alloy 2024-T4 is the most widely used aircraft alloy.  T (Temper designation): Age hardened (changes T1 to T10). For example: T4 :Solution treated and naturally aged.. T6:Solution treated and artifically aged. H: Cold worked. F: As fabricated (hot worked, forged, cast, etc.)  There are also prepcipitation-hardened Al-Li alloys. They are new generation alloys and they have low density (2.5 g/cm3) and high elastic modulus. *** PLEASE DO NOT MEMORIZE marked AAN codes!!! 8  Copper has very well thermal and electrical conductivity. Pure copper is red.  Unalloyed copper is so soft and ductile, that is difficult to machine; also it has an almost unlimited capacity to be cold worked.  Its corrosion resistance in many environments including ambient atmosphere, seawater and some chemicals is highly good.  The mechanical and corrosion-resistance properties might be developed by alloying. 9  Cu alloys BRASS BRONZE BERYLIUM COPPER COPPER-NICKELS  Brass is Cu-Zn alloy of  Bronzes are alloys of Cu and  1.0-2.5% Be  30% Ni 5-40% Zn. several other elements, such as Sn,  Berylium coppers are the  Nickel produces a Al, Si, and Ni. most common heat treatable silver color. Zinc additions produce a  Tin bronze (Cu-Sn), (10%Sn, 2%Zn) Cu alloys.  Applications: yellow color.  Silicon bronze (Cu-Si) Brasses are the most common  Aluminum bronze (Cu-Al)  Their tensile strengths are Condenser and heat copper alloys.  Bronzes are very good wear as high as 1035 MPa. exchanger components,  They are soft, ductile and resistant with low coefficient  Applications of these saltwater piping. easily cold worked. friction. coppers include jet landing  Some of the common uses for They are utilized when in addition gear bearing, springs, surgical to corrosion resistance, good tensile and dental instruments. brass alloys include jewelry, properties are required. cartridge casings, radiators and coins. 10  Magnesium is the lightest of all the structural engineering materials. Therefore, its alloys are used in aircraft and missile applications.  In many environments, the corrosion resistance of Mg approaches that of aluminum; however, exposure to salts, such as. that near a marine environment, causes rapid deterioration.  Its alloys are difficult to deform by cold working at room temperature. Consequently, most fabrication is by casting or hot working at temperatures between 200 and 3500C. 11  Its alloys are also classified as either cast or wrought, and some of them are heat treatable.  Some applications: in automobiles (steering wheels, columns, seat frames, transmission cases), in TV-computers equipments (laptop computers, camcorders, TV sets), bicyles, sporting goods, printing and textile machinery.  Very good for die casting, can be welded and riveted.  Mg is an alloying element in various nonferrous metals. Generally used in alloys with Al.  Fine Mg powders ignite easily when heated in air. In other words, they have very low flash point. Therefore, they should be handed with care (precautions must be taken when machining, grinding or sand casting magnesiım alloys) 12 13  Titanium and its alloys  Titanium is a relatively light metal.  Ti alloys are extremely strong  Ti is highly ductile (up to 25% elongation), easy forged and machined. It retains good strength at elevated temperature (it can be used as aircraft and missile components)  The major limitation of Ti is its chemical reactivity with other materials, such as O,N, and H, at elevated temperatures, and so special techniques must be used to cast and work the metal. Therefore, Ti alloys are expensive.  In spite of their high temperature reactivity, the corrosion resistance of Ti alloys at normal temperatures (below 500 0C) is excellent. Protective TiO2 film provides excellent resistance to corrosion and contamination below 535 0C.(It is used as marine components and implants) 14  Titanium and its alloys  It is a good alloying element in steel.  They are commonly utilized in airplane structures, jet engines, racing cars, biomedical implants (such as orthopedic implants), and in chemical and petroleum industries.  The Ti-6Al-4V alloy is the most-extensively used Ti alloy, since it combines high strength with good workability (about 1200 MPa, heat treated and aged). 15  Nickel (Ni) is similar to iron in many respects. It is magnetic, and its modulus of elasticity is virtually the same as that of iron and steel. However, it is much more corrosion resistant, and the high temperature properties of its alloys are generally superior. Because of its corrosion-resistant characteristics, it is widely used as an alloying element in steel, such as stainless steel, and as a plating metal on other metals such as plain carbon steel. 16  Alloys of nickel are commercially important for corrosion resistance and high temperature performance. In addition, a number of superalloys are based on nickel (Section 6.4). 17 ZINC, LEAD AND TIN 18  The superalloys are a group of high-performance alloys. Conventional room temperature strength is usually not the important criterion for these metals. Their high temperature performance is what distinguishes them; tensile strength, hot hardness, creep resistance, and corrosion resistance at very elevated temperatures are the mechanical properties of interest. Operating temperatures are often in the vicinity of 1100C (2000F). These metals are widely used in gas turbines—jet and rocket engines, steam turbines, and nuclear power plants—systems in which operating efficiency increases with higher temperatures. 19 The superalloys are usually divided into three groups, according to their principal constituent: iron, nickel, or cobalt: Iron-based alloys have iron as the main ingredient, although in some cases the iron is less than 50% of the total composition. Nickel-based alloys generally have better high temperature strength than alloy steels. Nickel is the base metal. The principal alloying elements are chromium and cobalt; lesser elements include aluminum, titanium, molybdenum, niobium (Nb), and iron. Somefamiliar names in this group include Inconel, Hastelloy, andRene 41. Cobalt-based alloys consist of cobalt (around 40%) and chromium (perhaps 20%) as their main components. Other alloying elements include nickel, molybdenum, and tungsten. 20 21