other nonferrous alloys
Other alloys cover a wide range, including several complex high-tech alloys. Aluminum alloys for casting frequently contain silicon (for improved fluidity), magnesium (for corrosion resistance), copper (for hardness and strength), zinc (for hardness and strength) or nickel (for dimensional stability and high-temperature strength), alone or in various combinations. Non-heat-treatable wrought aluminum alloys derive their hardness from manganese, silicon, iron and magnesium. Heat-treatable aluminum alloys may contain copper, magnesium, zinc or silicon, alone or in combination. Components for use in aircraft jet engines and giant power generating turbine blades employ aluminum-nickel and aluminum-titanium alloy systems. Duralumin, used extensively in aircraft bodies, is a strong lightweight aluminum alloy containing 3% to 4% copper and small amounts of magnesium, manganese and sometimes silicon. Titanium alloyed with 5% aluminum and 2.5% tin results in an alloy possessing high strength at high temperatures; titanium alloyed with 8% aluminum plus vanadium plus molybdenum creates a useful low temperature alloy. Nitinol (an acronym for Nickel Titanium Naval Ordinance Laboratory) is a family of intermetallic materials that contain a nearly equal mixture of nickel (55 wt. %) and titanium. Other elements can be added to adjust or "tune" the material properties. Nitinol exhibits unique behavior, including "shape memory" and "superelasticity". Binary Nitinol alloys, when processed correctly, are at their optimum superelastic behavior at body temperature, and are therefore useful in medical devices. Nickel silver consists of 55% to 65% copper, 10% to 18% nickel and 17% to 27% zinc, but no silver. Lead is often hardened with antimony. Pewter is an alloy of tin hardened with antimony and copper, and sometimes bismuth. Other tin alloys are used in bearings, and in type metal, composed of varying amounts of antimony, tin and lead, often with trace quantities of copper. Britannia metal, an alloy composed approximately of 93 percent tin, 5 percent antimony, and 2 percent copper, is used for making various utensils, including teapots, jugs, drinking vessels, candlesticks, and urns, and for official maces. Similar in color to pewter, britannia metal is harder, stronger, and easier to work than other tin alloys; it can be worked from sheets, like silver, or spun on a lathe. Babbitt metal describes any of several tin- or lead-based alloys used as bearing material for axles and crankshafts, based on the tin alloy invented in 1839 by Isaac Babbitt for use in steam engines. Modern babbitts, which provide a low-friction lining for bearing shells made of stronger metals such as cast iron, steel, or bronze, may be made of: (1) high-tin alloys with small quantities of antimony and copper; (2) high-lead alloys containing antimony, arsenic, and tin; and (3) intermediate tin-lead alloys with antimony and copper. Tin babbitts can be used at higher temperatures than the cheaper lead alloys, but most babbitts cannot endure prolonged use in high-performance internal-combustion engines, for which bearings are now made with linings of copper and aluminum alloys. The Alnico group, composed of iron, cobalt, nickel and aluminum, provides alloys for permanent magnets. Other trademarked and non-trademarked permanent magnet alloys include Alcomax, Ticonal, cunife and cunico. A cobalt-samarium alloy is used to make a magnet unparalleled in its resistance to demagnetization. Nichrome, used for electric heating filaments, is a chromium-nickel alloy with low conductance and high resistance to oxidation in air. Stellite, very hard even at high temperatures, combines cobalt, chromium, tungsten and molybdenum. Tungsten alloys provide barrels for darts. Non-steel high speed cutting tool alloys combine tungsten, chromium and cobalt. Deep-sea diving suits are constructed of magnesium alloys. The Heusler alloys, named after 19th-century German mining engineer and chemist Fritz Heusler, were the first magnetic alloys composed of metals that, in their pure state, are not magnetic. Containing 18% to 25% manganese plus copper and aluminum or zinc, they are the strongest nonferrous metal alloys. The ratio of Heusler alloys is approximately two parts of copper, one of manganese, and one of tin. The tin may be replaced by aluminum, arsenic, antimony, bismuth, or boron; the copper may be replaced by silver. Manganese copper (75% copper and 25% manganese) has great electrical resistance. Manganin (83% copper, 14% manganese and 3% nickel) has a nearly temperature-independent electrical resistance and a very low heat-expansion coefficient; Constantan, an alloy of 55% copper and 45% nickel, has similar properties. Kovar«, also known as Rodar«, is a proprietary low expansion alloy considting of 2% (max.) carbon, 30% manganese, 20% silicon, 29% nickel, 17% Cobalt, and the balance iron. It has been widely used for making hermetic seals with the harder Pyrex glass and ceramic materials such as in power tubes, microwave tubes, transistors, and diodes, as well as integrated circuits. Zircaloy is a tin-nickel-iron-chromium alloy widely used by the nuclear industry as pipes and cladding for fuel elements. Thorium alloyed with magnesium forms a lightweight alloy used in aircraft and rocket construction.