metallurgical study

- analog study

SUBJECT AREA: Metallurgy

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After graduating in chemistry from the Ecole Polytechnique in 1887, Charpy continued to work there on the physical chemistry of solutions for his doctorate. He joined the Laboratoire d'Artillerie de la Marine in 1892 and began to study the structure and mechanical properties of various steels in relation to their previous heat treatment. His first memoir, on the mechanical properties of steels quenched from various temperatures, was published in 1892 on the advice of Henri Le Chatelier. He joined the Compagnie de Chatillon Commentry Fourchamboult et Decazeville at their steelworks in Imphy in 1898, shortly after the discovery of Invar by G.E. Guillaume. Most of the alloys required for this investigation had been prepared at Imphy, and their laboratories were therefore well equipped with sensitive and refined dilatometric facilities. Charpy and his colleague L.Grenet utilized this technique in many of their earlier investigations, which were largely concerned with the transformation points of steel. He began to study the magnetic characteristics of silicon steels in 1902, shortly after their use as transformer laminations had first been proposed by Hadfield and his colleagues in 1900. Charpy was the first to show that the magnetic hysteresis of these alloys decreased rapidly as their grain size increased.

The first details of Charpy's pendulum impact testing machine were published in 1901, about two years before Izod read his paper to the British Association. As with Izod's machine, the energy of fracture was measured by the retardation of the pendulum. Charpy's test pieces, however, unlike those of Izod, were in the form of centrally notched beams, freely supported at each end against rigid anvils. This arrangement, it was believed, transmitted less energy to the frame of the machine and allowed the energy of fracture to be more accurately measured. In practice, however, the blow of the pendulum in the Charpy test caused visible distortion in the specimen as a whole. Both tests were still widely used in the 1990s.

In 1920 Charpy left Imphy to become Director-General of the Compagnie des Aciéries de la Marine et Homecourt. After his election to the Académie des Sciences in 1918, he came to be associated with Floris Osmond and Henri Le Chatelier as one of the founders of the "French School of Physical Metallurgy". Around the turn of the century he had contributed much to the development of the metallurgical microscope and had helped to introduce the Chatelier thermocouple into the laboratory and to industry. He also popularized the use of platinum-wound resistance furnaces for laboratory purposes. After 1920 his industrial responsibilities increased greatly, although he continued to devote much of his time to teaching at the Ecole Supérieure des Mines in Paris, and at the Ecole Polytechnique. His first book, Leçons de Chimie (1892, Paris), was written at the beginning of his career, in association with H.Gautier. His last, Notions élémentaires de sidérurgie (1946, Paris), with P.Pingault as co-author, was published posthumously.

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SUBJECT AREA: Metallurgy

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After a private education, Percy went to Paris in 1834 to study medicine and to attend lectures on chemistry by Gay-Lussac and Thenard. After 1838 he studied medicine at Edinburgh, obtaining his MD in 1839. In that year he was appointed Professor of Chemistry at Queen's College, Birmingham, moving to Queen's Hospital at Birmingham in 1843. During his time at Birmingham, Percy became well known for his analysis of blast furnace slags, and was involved in the manufacture of optical glass. On 7 June 1851 Percy was appointed Metallurgical Professor and Teacher at the Museum of Practical Geology established in Jermyn Street, London, and opened in May 1851. In November of 1851, when the Museum became the Government (later Royal) School of Mines, Percy was appointed Lecturer in Metallurgy. In addition to his work at Jermyn Street, Percy lectured on metallurgy to the Advanced Class of Artillery at Woolwich from 1864 until his death, and from 1866 he was Superintendent of Ventilation at the Houses of Parliament. He served from 1861 to 1864 on the Special Committee on Iron set up to examine the performance of armour-plate in relation to its purity, composition and structure.

Percy is best known for his metallurgical text books, published by John Murray. Volume I of Metallurgy, published in 1861, dealt with fuels, fireclays, copper, zinc and brass; Volume II, in 1864, dealt with iron and steel; a volume on lead appeared in 1870, followed by one on fuels and refractories in 1875, and the first volume on gold and silver in 1880. Further projected volumes on iron and steel, noble metals, and on copper, did not materialize. In 1879 Percy resigned from his School of Mines appointment in protest at the proposed move from Jermyn Street to South Kensington. The rapid growth of Percy's metallurgical collection, started in 1839, eventually forced him to move to a larger house. After his death, the collection was bought by the South Kensington (later Science) Museum. Now comprising 3,709 items, it provides a comprehensive if unselective record of nineteenth-century metallurgy, the most interesting specimens being those of the first sodium-reduced aluminium made in Britain and some of the first steel produced by Bessemer in Baxter House. Metallurgy for Percy was a technique of chemical extraction, and he has been criticized for basing his system of metallurgical instruction on this assumption. He stood strangely aloof from new processes of steel making such as that of Gilchrist and Thomas, and tended to neglect early developments in physical metallurgy, but he was the first in Britain to teach metallurgy as a discipline in its own right.

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SUBJECT AREA: Metallurgy

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His family emigrated to Australia when he was 5 years old. He was educated at Wesley College, Melbourne, and attended Queen's College, University of Melbourne, graduating in physics and engineering in 1897. As an 1851 Exhibitioner he then spent three years at St John's College, Cambridge, under Sir Alfred Ewing, where he studied the microstructure of deformed metal crystals and abandoned his original intention of becoming a civil engineer. Rosenhain was the first to observe the slip-bands in metal crystals, and in the Bakerian Lecture delivered jointly by Ewing and Rosenhain to the Royal Society in 1899 it was shown that metals deformed plastically by a mechanism involving shear slip along individual crystal planes. From this conception modern ideas on the plasticity and recrystallization of metals rapidly developed. On leaving Cambridge, Rosenhain joined the Birmingham firm of Chance Brothers, where he worked for six years on optical glass and lighthouse-lens systems. A book, Glass Manufacture, written in 1908, derives from this period, during which he continued his metallurgical researches in the evenings in his home laboratory and published several papers on his work.

In 1906 Rosenhain was appointed Head of the Metallurgical Department of the National Physical Laboratory (NPL), and in 1908 he became the first Superintendent of the new Department of Metallurgy and Metallurgical Chemistry. Many of the techniques he introduced at Teddington were described in his Introduction to Physical Metallurgy, published in 1914. At the outbreak of the First World War, Rosenhain was asked to undertake work in his department on the manufacture of optical glass. This soon made it possible to manufacture optical glass of high quality on an industrial scale in Britain. Much valuable work on refractory materials stemmed from this venture. Rosenhain's early years at the NPL were, however, inseparably linked with his work on light alloys, which between 1912 and the end of the war involved virtually all of the metallurgical staff of the laboratory. The most important end product was the well-known "Y" Alloy (4% copper, 2% nickel and 1.5% magnesium) extensively used for the pistons and cylinder heads of aircraft engines. It was the prototype of the RR series of alloys jointly developed by Rolls Royce and High Duty Alloys. An improved zinc-based die-casting alloy devised by Rosenhain was also used during the war on a large scale for the production of shell fuses.

After the First World War, much attention was devoted to beryllium, which because of its strength, lightness, and stiffness would, it was hoped, become the airframe material of the future. It remained, however, too brittle for practical use. Other investigations dealt with impurities in copper, gases in aluminium alloys, dental alloys, and the constitution of alloys. During this period, Rosenhain's laboratory became internationally known as a centre of excellence for the determination of accurate equilibrium diagrams.

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SUBJECT AREA: Metallurgy, Mining and extraction technology

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Educated at Wittenberg University during 1547–8, Ercker obtained in 1554, through one of his wife's relatives, the post of Assayer from the Elector Augustus at Dresden. From then on he took a succession of posts in mining and metallurgy. In 1555 he was Chief Consultant and Supervisor of all matters relating to mines, but for some unknown reason was demoted to Warden of the Mint at Annaberg. In 1558 he travelled to the Tyrol to study the mines in that region, and in the same year Prince Henry of Brunswick appointed him Warden, then Master, of the Mint at Goslar. Ercker later moved to Prague where, through another of his wife's relatives, he was appointed Control Tester at Kutna Hora. It was there that he wrote his best-known book, Die Beschreibung allfürnemisten mineralischen Ertz, which drew him to the attention of the Emperor Maximilian, who made him Courier for Mining and a clerk of the Supreme Court of Bohemia. The next Emperor, Rudolf II, a noted patron of science and alchemy, promoted Ercker to Chief Inspector of Mines and ennobled him in 1586 with the title Von Schreckenfels'. His second wife managed the mint at Kutna Hora and his two sons became assayers. These appointments gained him much experience of the extraction and refining of metals. This first bore fruit in a book on assaying, Probierbüchlein, printed in 1556, followed by one on minting, Münzbuch, in 1563. His main work, Die Beschreibung, was a systematic review of the methods of obtaining, refining and testing the alloys and minerals of gold, silver, copper, antimony, mercury and lead. The preparation of acids, salts and other compounds is also covered, and his apparatus is fully described and illustrated. Although Ercker used Agricola's De re metattica as a model, his own work was securely based on his practical experience. Die Beschreibung was the first manual of analytical and metallurgical chemistry and influenced later writers such as Glauber on assaying. After the first edition in Prague came four further editions in Frankfurt-am-Main.

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SUBJECT AREA: Metallurgy

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Hunter arrived in England in 1902, the seventh in the succession of New Zealand students nominated for the 1851 Exhibition science research scholarships (the third, in 1894, having been Ernest Rutherford). He intended to study the metallurgy of tellurides at the Royal School of Mines, but owing to the death of the professor concerned, he went instead to University College London, where his research over two years involved the molecular aggregation of liquified gases. In 1904–5 he spent a third year in Göttingen, Paris and Karlsruhe. Hunter then moved to the USA, beginning work in 1906 with the General Electric Company in Schenectady. His experience with titanium came as part of a programme to try to discover satisfactory lamp-filament materials. He and his colleagues achieved more success in producing moderately pure titanium than previous workers had done, but found the metal's melting temperature inadequate. However, his research formed the basis for the "Hunter sodium process", a modern method for producing commercial quantities of titanium. In 1908 he was appointed Assistant Professor of Electrochemistry and Physics at Rensselaer Polytechnic Institute in Troy, New York, where he was to remain until his retirement in 1949 as Dean Emeritus. In the 1930s he founded and headed the Institute's Department of Metallurgical Engineering. As a consultant, he was associated with the development of Invar, Managanin and Constantan alloys.

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SUBJECT AREA: Metallurgy

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The son of a distinguished engineer, Le Chatelier entered the Ecole Polytechnique in 1869: after graduating in the Faculty of Mines, he was appointed Professor at the Ecole Supérieure des Mines in 1877. After assisting Deville with the purification of bauxite in unsuccessful attempts to obtain aluminium in useful quantities, Le Chatelier's work covered a wide range of topics and he gave much attention to the driving forces of chemical reactions. Between 1879 and 1882 he studied the mechanisms of explosions in mines, and his doctorate in 1882 was concerned with the chemistry and properties of hydraulic cements. The dehydration of such materials was studied by thermal analysis and dilatometry. Accurate temperature measurement was crucial and his work on the stability of thermocouples, begun in 1886, soon established the superiority of rhodium-platinum alloys for high-temperature measurement. The most stable combination, pure platinum coupled with a 10 per cent rhodium platinum positive limb, became known as Le Chatelier couple and was in general use throughout the industrial world until c. 1922. For applications where thermocouples could not be used, Le Chatelier also developed the first practical optical pyrometer. From hydraulic cements he moved on to refractory and other ceramic materials which were also studied by thermal analysis and dilatometry. By 1888 he was systematically applying such techniques to metals and alloys. Le Chatelier, together with Osmond, Worth, Genet and Charpy, was a leading member of that group of French investigators who established the new science of physical metallurgy between 1888 and 1900. Le Chatelier was determining the recalescence points in steels in 1888 and was among the first to study intermetallic compounds in a systematic manner. To facilitate such work he introduced the inverted microscope, upon which metallographers still depend for the routine examination of polished and etched metallurgical specimens under incident light. The principle of mobile equilibrium, developed independently by Le Chatelier in 1885 and F.Braun in 1886, stated that if one parameter in an equilibrium situation changed, the equilibrium point of the system would move in a direction which tended to reduce the effect of this change. This provided a useful qualitative working tool for the experimentalists, and was soon used with great effect by Haber in his work on the synthesis of ammonia.

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SUBJECT AREA: Chemical technology

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His family, of modest means, moved in 1864 to Meaux, where he attended the municipal college; he returned to Paris before completing his education and apprenticed himself to a pharmacist. In 1872 he began work as a laboratory assistant at the Musée d'Histoire Naturelle, while continuing studies in chemistry. He qualified as a pharmacist at the Ecole Supérieure de Pharmacie in 1879, and by this time he had decided that his main interest was inorganic chemistry. His early investigations concerned the oxides of iron and related metals; his work attracted the favourable attention of Sainte-Claire Deville and was the subject of his doctoral thesis. In 1882 Moissan married Leonie Lugan, whose father provided generous financial support, enabling him to pursue his researches with greater freedom and security. He became, successively, Professor of Toxicology at the Ecole in 1886 and of Inorganic Chemistry in 1899. In 1884 Moissan began both his investigation of the compounds of fluorine and his attempts to isolate the highly reactive element itself. Previous attempts by chemists had ended in failure and sometimes injury. Moissan's health, too, was affected, but in June 1886 he succeeded in isolating fluorine by electrolysing potassium fluoride in hydrogen fluoride at −50°C (−58°F) in platinum apparatus. He was then able to prepare further compounds of fluorine, some of technological importance, such as carbon tetrafluoride. At the same time, Moissan turned his attention to the making of artificial diamonds. To achieve this, he devised his celebrated electric-arc furnace; this was first demonstrated in December 1892 and consisted of two lime blocks placed one above the other, with a cavity for a crucible and two grooves for carbon electrodes, and could attain a temperature of 3,500°C (6,332°F). It seemed at first that he had succeeded in making diamonds, but this attempt is now regarded as a failure. Nevertheless, with the aid of his furnace he was able to produce and study many substances of technological importance, including refractory oxides, borides and carbides, and such metals as manganese, chromium, uranium, tungsten, vanadium, molybdenum, titanium and zirconium; many of these materials had useful applications in the chemical and metallurgical industries (e.g. calcium carbide became the main source of acetylene).

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