Prehistory Copper, which occurs in native form, may have been the first metal discovered given its distinctive appearance, heaviness, and malleability. Gold, silver, iron (as meteoric iron), and lead were likewise discovered in prehistory. Forms of
brass, an alloy of copper and zinc made by concurrently smelting the ores of these metals, originate from this period (although pure zinc was not isolated until the 13th century). The malleability of the solid metals led to the first attempts to craft metal ornaments, tools, and weapons. Meteoric iron containing nickel was discovered from time to time and, in some respects this was superior to any industrial steel manufactured up to the 1880s when alloy steels become prominent. File:NatCopper.jpg|
Native copper File:Gold-crystals.jpg|Gold crystals File:Silver crystal.jpg|Crystalline silver File:Widmanstatten hand.jpg|A slice of meteoric iron File:Lead electrolytic and 1cm3 cube.jpg|alt=Three, dark broccoli shaped clumps of oxidised lead with grossly distended buds, and a cube of lead which has a dull silvery appearance.|
oxidised leadnodules and 1 cm3 cube File:Akan MHNT.AC.AF.29.jpg|A brass weight (35 g)
Antiquity showing either
Poseidon or
Zeus, c. 460 BCE,
National Archaeological Museum,
Athens. The figure is more than 2 m in height.|alt=Refer to caption The discovery of
bronze (an alloy of copper with arsenic or tin) enabled people to create metal objects which were harder and more durable than previously possible. Bronze tools, weapons, armor, and
building materials such as decorative tiles were harder and more durable than their stone and copper ("
Chalcolithic") predecessors. Initially, bronze was made of copper and
arsenic (forming
arsenic bronze) by smelting naturally or artificially mixed ores of copper and arsenic. The earliest
artifacts so far known come from the
Iranian plateau in the fifth millennium BCE. It was only later that
tin was used, becoming the major non-copper ingredient of bronze in the late third millennium BCE. Pure tin itself was first isolated in 1800 BCE by Chinese and Japanese metalworkers. Mercury was known to ancient Chinese and Indians before 2000 BCE, and found in Egyptian tombs dating from 1500 BCE. The earliest known production of steel, an iron-carbon alloy, is seen in pieces of ironware excavated from an
archaeological site in
Anatolia (
Kaman-Kalehöyük) which are nearly 4,000 years old, dating from 1800 BCE. From about 500 BCE sword-makers of
Toledo, Spain, were making early forms of
alloy steel by adding a mineral called
wolframite, which contained tungsten and manganese, to iron ore (and carbon). The resulting
Toledo steel came to the attention of Rome when used by Hannibal in the
Punic Wars. It soon became the basis for the weaponry of Roman legions; such swords were, "stronger in composition than any existing sword and, because… [they] would not break, provided a psychological advantage to the Roman soldier."
In pre-Columbian America, objects made of
tumbaga, an alloy of copper and gold, started being produced in Panama and Costa Rica between 300 and 500 CE. Small metal sculptures were common and an extensive range of tumbaga (and gold) ornaments comprised the usual regalia of persons of high status. At around the same time indigenous Ecuadorians were combining gold with a naturally occurring platinum alloy containing small amounts of palladium, rhodium, and iridium, to produce miniatures and masks of a white gold-platinum alloy. The metal workers involved heated gold with
grains of the platinum alloy until the gold melted. After cooling, the resulting conglomeration was hammered and reheated repeatedly until it became homogenous, equivalent to melting all the metals (attaining the melting points of the platinum group metals concerned was beyond the technology of the day). File:Tin-2.jpg|A droplet of solidified molten tin File:Pouring liquid mercury bionerd.jpg|alt=A silvery molasses-like liquid being poured into a circular container with a height equivalent to a smaller coin on its edge|
Mercury beingpoured into a
petri dish File:25 litrai en électrum représentant un trépied delphien.jpg|Electrum, a natural alloy of silver and gold, was often used for making coins. Shown is the Greek god
Apollo, and on the obverse, a
Delphi tripod (–305 BCE). File:Passover Plate (4047010755).jpg|A plate made of
pewter, an alloy of 85–99% tin and (usually) copper. Pewter was first used around the beginning of the Bronze Age in the Near East. File:Museo del Oro - Tolima pectoral.jpg|A pectoral (ornamental breastplate) made of
tumbaga, an alloy of gold and copper
Ancient Greece (384–322 BCE) categorized substances found in the earth as either metals or minerals. Around 340 BCE, in Book III of his treatise
Meteorology, the ancient Greek philosopher
Aristotle categorized substances found within the Earth into metals and minerals. The latter category included various minerals such as
realgar,
ochre,
ruddle, sulfur,
cinnabar, and other substances that he referred to as "stones which cannot be melted".
Middle Ages Arabic and medieval
alchemists believed that all metals and matter were composed of the principle of sulfur, the father of all metals and carrying the combustible property, and the principle of mercury, the mother of all metals and carrier of the liquidity, fusibility, and volatility properties. These principles were not necessarily the common substances
sulfur and
mercury found in most laboratories. This theory reinforced the belief that all metals were destined to become gold in the bowels of the earth through the proper combinations of heat, digestion, time, and elimination of contaminants, all of which could be developed and hastened through the knowledge and methods of alchemy. Arsenic, zinc, antimony, and bismuth became known, although these were at first called semimetals or bastard metals on account of their immalleability.
Albertus Magnus is believed to have been the first to isolate arsenic from a compound in 1250, by heating soap together with
arsenic trisulfide. Metallic zinc, which is brittle if impure, was isolated in India by 1300 AD. The first description of a procedure for isolating antimony is in the 1540 book
De la pirotechnia by
Vannoccio Biringuccio. Bismuth was described by Agricola in
De Natura Fossilium (c. 1546); it had been confused in early times with tin and lead because of its resemblance to those elements. File:Arsen 1a.jpg|Arsenic, sealed in a container to prevent tarnishing File:Zinc fragment sublimed and 1cm3 cube.jpg|Zinc fragments and a 1 cm3 cube File:Antimony-4.jpg|Antimony, showing its brilliant lustre File:Wismut Kristall und 1cm3 Wuerfel.jpg|Bismuth in crystalline form, with a very thin oxidation layer, and a 1 cm3 bismuth cube
The Renaissance '', 1555|alt=The title page of De re metallica, which is written in Latin , in
Oak Ridge, Tennessee|alt=A disc of uranium being held by gloved hands The first systematic text on the arts of mining and metallurgy was
De la Pirotechnia (1540) by
Vannoccio Biringuccio, which treats the examination, fusion, and working of metals. Sixteen years later,
Georgius Agricola published
De Re Metallica in 1556, an account of the profession of mining, metallurgy, and the accessory arts and sciences, an extensive treatise on the chemical industry through the sixteenth century. He gave the following description of a metal in his
De Natura Fossilium (1546): Metal is a mineral body, by nature either liquid or somewhat hard. The latter may be melted by the heat of the fire, but when it has cooled down again and lost all heat, it becomes hard again and resumes its proper form. In this respect it differs from the stone which melts in the fire, for although the latter regain its hardness, yet it loses its pristine form and properties. Traditionally there are six different kinds of metals, namely gold, silver, copper, iron, tin, and lead. There are really others, for
quicksilver is a metal, although the Alchemists disagree with us on this subject, and
bismuth is also. The ancient Greek writers seem to have been ignorant of bismuth, wherefore Ammonius rightly states that there are many species of metals, animals, and plants which are unknown to us.
Stibium when smelted in the crucible and refined has as much right to be regarded as a proper metal as is accorded to lead by writers. If when smelted, a certain portion be added to tin, a bookseller's alloy is produced from which the type is made that is used by those who print books on paper. Each metal has its own form which it preserves when separated from those metals which were mixed with it. Therefore neither
electrum nor Stannum [not meaning our tin] is of itself a real metal, but rather an alloy of two metals. Electrum is an alloy of gold and silver, Stannum of lead and silver. And yet if silver be parted from the electrum, then gold remains and not electrum; if silver be taken away from Stannum, then lead remains and not Stannum. Whether brass, however, is found as a native metal or not, cannot be ascertained with any surety. We only know of the artificial brass, which consists of copper tinted with the colour of the mineral
calamine. And yet if any should be dug up, it would be a proper metal. Black and white copper seem to be different from the red kind. Metal, therefore, is by nature either solid, as I have stated, or fluid, as in the unique case of quicksilver. But enough now concerning the simple kinds. Platinum, the third precious metal after gold and silver, was discovered in Ecuador during the period 1736 to 1744 by the Spanish astronomer
Antonio de Ulloa and his colleague the mathematician
Jorge Juan y Santacilia. Ulloa was the first person to write a scientific description of the metal, in 1748. In 1789, the German chemist
Martin Heinrich Klaproth isolated an oxide of uranium, which he thought was the metal itself. Klaproth was subsequently credited as the discoverer of uranium. It was not until 1841, that the French chemist
Eugène-Melchior Péligot, prepared the first sample of uranium metal. Henri Becquerel subsequently discovered radioactivity in 1896 using uranium. In the 1790s,
Joseph Priestley and the Dutch chemist
Martinus van Marum observed the effect of metal surfaces on the dehydrogenation of alcohol, a development which subsequently led, in 1831, to the industrial scale synthesis of sulphuric acid using a platinum catalyst. In 1803, cerium was the first of the
lanthanide metals to be discovered, in Bastnäs, Sweden by
Jöns Jakob Berzelius and
Wilhelm Hisinger, and independently by Martin Heinrich Klaproth in Germany. The lanthanide metals were regarded as oddities until the 1960s when methods were developed to more efficiently separate them from one another. They have subsequently found uses in cell phones, magnets, lasers, lighting, batteries, catalytic converters, and in other applications enabling modern technologies. Other metals discovered and prepared during this time were cobalt, nickel, manganese, molybdenum, tungsten, and chromium; and some of the
platinum group metals, palladium, osmium, iridium, and rhodium.
Light metallic elements All elemental metals discovered before 1809 had relatively high densities; their heaviness was regarded as a distinguishing criterion. From 1809 onward, light metals such as sodium, potassium, and strontium were isolated. Their low densities challenged conventional wisdom as to the nature of metals. They behaved chemically as metals however, and were subsequently recognized as such. Aluminium was discovered in 1824 but it was not until 1886 that an industrial large-scale production method was developed. Prices of aluminium dropped and aluminium became widely used in jewelry, everyday items, eyeglass frames, optical instruments, tableware, and foil in the 1890s and early 20th century. Aluminium's ability to form hard yet light alloys with other metals provided the metal many uses at the time. During World War I, major governments demanded large shipments of aluminium for light and strong airframes. While pure metallic titanium (99.9%) was first prepared in 1910 it was not used outside the laboratory until 1932. In the 1950s and 1960s, the Soviet Union pioneered the use of titanium in military and submarine applications as part of programs related to the Cold War. Starting in the early 1950s, titanium came into use in military aviation, particularly in high-performance jets, starting with aircraft such as the
F-100 Super Sabre and
Lockheed A-12 and
SR-71. Metallic scandium was produced for the first time in 1937. The first pound of 99% pure scandium metal was produced in 1960. Production of aluminium-scandium alloys began in 1971 following a U.S. patent. Aluminium-scandium alloys were also developed in the USSR. File:Na (Sodium).jpg|Chunks of sodium File:Potassium-2.jpg|Potassium pearls under paraffin oil. Size of the largest pearl is 0.5 cm. File:Strontium destilled crystals.jpg|Strontium crystals File:Aluminium-4.jpg|Aluminium chunk,2.6 grams, File:Titan-crystal bar.JPG|A bar of titanium crystals File:Scandium sublimed dendritic and 1cm3 cube.jpg|Scandium, including a 1 cm3 cube
The age of steel ,
Pennsylvania. The modern era in
steelmaking began with the introduction of
Henry Bessemer's
Bessemer process in 1855, the raw material for which was pig iron. His method let him produce steel in large quantities cheaply, thus
mild steel came to be used for most purposes for which wrought iron was formerly used. The
Gilchrist-Thomas process (or
basic Bessemer process) was an improvement to the Bessemer process, made by lining the converter with a
basic material to remove phosphorus. Due to its high
tensile strength and low cost, steel came to be a major component used in
buildings,
infrastructure,
tools,
ships,
automobiles,
machines, appliances, and
weapons. In 1872, the Englishmen Clark and Woods patented an alloy that would today be considered a
stainless steel. The corrosion resistance of iron-chromium alloys had been recognized in 1821 by French metallurgist
Pierre Berthier. He noted their resistance against attack by some acids and suggested their use in cutlery. Metallurgists of the 19th century were unable to produce the combination of low carbon and high chromium found in most modern stainless steels, and the high-chromium alloys they could produce were too brittle to be practical. It was not until 1912 that the industrialization of stainless steel alloys occurred in England, Germany, and the United States.
The last stable metallic elements By 1900 three metals with
atomic numbers less than lead (#82), the heaviest stable metal, remained to be discovered: elements 71, 72, 75.
Von Welsbach, in 1906, proved that the old ytterbium also contained a new element (#71), which he named
cassiopeium.
Urbain proved this simultaneously, but his samples were very impure and only contained trace quantities of the new element. Despite this, his chosen name
lutetium was adopted. In 1908, Ogawa found element 75 in thorianite but assigned it as element 43 instead of 75 and named it
nipponium. In 1925 Walter Noddack, Ida Eva Tacke, and Otto Berg announced its separation from gadolinite and gave it the present name,
rhenium. Georges Urbain claimed to have found element 72 in rare-earth residues, while Vladimir Vernadsky independently found it in orthite. Neither claim was confirmed due to World War I, and neither could be confirmed later, as the chemistry they reported does not match that now known for
hafnium. After the war, in 1922, Coster and Hevesy found it by X-ray spectroscopic analysis in Norwegian zircon.
Hafnium was thus the last stable element to be discovered, though rhenium was the last to be correctly recognized. File:Lutetium sublimed dendritic and 1cm3 cube.jpg|Lutetium, including a 1 cm3 cube File:Rhenium single crystal bar and 1cm3 cube.jpg|Rhenium, including a 1 cm3 cube File:Hf-crystal bar.jpg|Hafnium, in the form of a 1.7 kg bar By the end of World War II scientists had synthesized four post-uranium elements, all of which are radioactive (unstable) metals: neptunium (in 1940), plutonium (1940–41), and curium and americium (1944), representing elements 93 to 96. The first two of these were eventually found in nature as well. Curium and americium were by-products of the Manhattan project, which produced the world's first atomic bomb in 1945. The bomb was based on the nuclear fission of uranium, a metal first thought to have been discovered nearly 150 years earlier.
Post-World War II developments Superalloys Superalloys composed of combinations of Fe, Ni, Co, and Cr, and lesser amounts of W, Mo, Ta, Nb, Ti, and Al were developed shortly after World War II for use in high performance engines, operating at elevated temperatures (above 650 °C (1,200 °F)). They retain most of their strength under these conditions, for prolonged periods, and combine good low-temperature ductility with resistance to corrosion or oxidation. Superalloys can now be found in a wide range of applications including land, maritime, and aerospace turbines, and chemical and petroleum plants.
Transcurium metals The successful development of the atomic bomb at the end of World War II sparked further efforts to synthesize new elements, nearly all of which are, or are expected to be, metals, and all of which are radioactive. It was not until 1949 that element 97 (
Berkelium), next after element 96 (
Curium), was synthesized by firing alpha particles at an americium target. In 1952, element 100 (
Fermium) was found in the debris of the first hydrogen bomb explosion; hydrogen, a nonmetal, had been identified as an element nearly 200 years earlier. Since 1952, elements 101 (
Mendelevium) to 118 (
Oganesson) have been synthesized.
Bulk metallic glasses A metallic glass (also known as an amorphous or glassy metal) is a solid metallic material, usually an alloy, with a disordered atomic-scale structure. Most pure and alloyed metals, in their solid state, have atoms arranged in a highly ordered crystalline structure. In contrast these have a non-crystalline glass-like structure. But unlike common glasses, such as window glass, which are typically electrical insulators, amorphous metals have good electrical conductivity. Amorphous metals are produced in several ways, including extremely rapid cooling, physical vapor deposition, solid-state reaction, ion irradiation, and mechanical alloying. The first reported metallic glass was an alloy (Au75Si25) produced at
Caltech in 1960. More recently, batches of amorphous steel with three times the strength of conventional steel alloys have been produced. Currently, the most important applications rely on the special magnetic properties of some ferromagnetic metallic glasses. The low magnetization loss is used in high-efficiency transformers. Theft control ID tags and other article surveillance schemes often use metallic glasses because of these magnetic properties.
Shape-memory alloys A shape-memory alloy (SMA) is an alloy that "remembers" its original shape and when deformed returns to its pre-deformed shape when heated. While the shape memory effect had been first observed in 1932, in an Au-Cd alloy, it was not until 1962, with the accidental discovery of the effect in a Ni-Ti alloy that research began in earnest, and another ten years before commercial applications emerged. SMA's have applications in robotics and automotive, aerospace, and biomedical industries. There is another type of SMA, called a ferromagnetic shape-memory alloy (FSMA), that changes shape under strong magnetic fields. These materials are of interest as the magnetic response tends to be faster and more efficient than temperature-induced responses.
Quasicrystalline alloys , the
dual of the
icosahedron|alt=A metallic regular dodecahedron In 1984, Israeli metallurgist
Dan Shechtman found an aluminium-manganese alloy having five-fold symmetry, in breach of crystallographic convention at the time which said that crystalline structures could only have two-, three-, four-, or six-fold symmetry. Due to reservation about the scientific community's reaction, it took Shechtman two years to publish the results for which he was awarded the Nobel Prize in Chemistry in 2011. Since this time, hundreds of quasicrystals have been reported and confirmed. They exist in many metallic alloys (and some polymers). Quasicrystals are found most often in aluminium alloys (Al-Li-Cu, Al-Mn-Si, Al-Ni-Co, Al-Pd-Mn, Al-Cu-Fe, Al-Cu-V, etc.), but numerous other compositions are also known (Cd-Yb, Ti-Zr-Ni, Zn-Mg-Ho, Zn-Mg-Sc, In-Ag-Yb, Pd-U-Si, etc.). Quasicrystals effectively have infinitely large unit cells.
Icosahedrite Al63Cu24Fe13, the first quasicrystal found in nature, was discovered in 2009. Most quasicrystals have ceramic-like properties including low electrical conductivity (approaching values seen in insulators) and low thermal conductivity, high hardness, brittleness, and resistance to corrosion, and non-stick properties. Quasicrystals have been used to develop heat insulation, LEDs, diesel engines, and new materials that convert heat to electricity. New applications may take advantage of the low coefficient of friction and the hardness of some quasicrystalline materials, for example embedding particles in plastic to make strong, hard-wearing, low-friction plastic gears. Other potential applications include selective solar absorbers for power conversion, broad-wavelength reflectors, and bone repair and prostheses applications where biocompatibility, low friction, and corrosion resistance are required. but did not succeed until 1955. Potential applications of CMAs include as heat insulation; solar heating; magnetic refrigerators; using waste heat to generate electricity; and coatings for turbine blades in military engines. because the
entropy increase of mixing is substantially higher when there is a larger number of elements in the mix, and their proportions are more nearly equal. Some alternative names, such as multi-component alloys, compositionally complex alloys and multi-principal-element alloys are also used in the literature. These alloys are currently the focus of significant attention in
materials science and engineering because they have potentially desirable properties. Furthermore, research indicates that some HEAs have considerably better
strength-to-weight ratios, with a higher degree of
fracture resistance,
tensile strength, and
corrosion and
oxidation resistance than conventional alloys. Although HEAs have been studied since the 1980s, research substantially accelerated starting in the 2010s.
MAX phase In a MAX phase,
M is an early transition metal,
A is an A group element (mostly group IIIA and IVA, or groups 13 and 14), and
X is either carbon or nitrogen. Examples are Hf2SnC and Ti4AlN3. Such alloys have high electrical and thermal conductivity, thermal shock resistance, damage tolerance, machinability, high elastic stiffness, and low thermal expansion coefficients. They can be polished to a metallic luster because of their excellent electrical conductivities. Some MAX phases are also highly resistant to chemical attack (e.g. Ti3SiC2) and high-temperature oxidation in air (Ti2AlC, Cr2AlC2, and Ti3AlC2). Potential applications for MAX phase alloys include: as tough, machinable, thermal shock-resistant refractories; high-temperature heating elements; coatings for electrical contacts; and neutron irradiation resistant parts for nuclear applications. ==See also==