An Encyclopedia of the History of Technology part 15. This one of a kind encyclopedia presents the entire field of technology from rudimentary agricultural tools to communication satellites in this first of its kind reference source. Following an introduction that discusses basic tools, devices, and mechanisms, the chapters are grouped into five parts that provide detailed information on materials, power and engineering, transportation, communication and calculation, and technology and society, revealing how different technologies have together evolved to produce enormous changes in the course of history | PART ONE MATERIALS Wilm noted that an aluminium alloy he was working on had the remarkable ability to harden slowly at room temperature after having previously been quenched from a temperature just below its melting point. The effect was observed quite fortuitously while Wilm working on a contract from the Prussian government was attempting to develop alloys for cartridge cases which were lighter than the 70 30 brass which was normally employed. Between 1909 and 1911 Wilm filed several Patent Applications and assigned his rights in this age-hardening invention to the Durener-Metallwerke in Duren who subsequently marketed the alloys under the trade name Duralumin. During the First World War large quantities of age-hardened aluminium alloys were used by the combatants first for Zeppelins and then for other types of aircraft. It was found that the strengthening reaction could be slowed down very significantly by refrigeration. This made it possible to quench aluminium alloy rivets and store them in the soft condition in a refrigerator. The age hardening process began only after the rivet head had been closed after insertion into the aircraft structure. A great deal of the metallurgical research stimulated by the introduction of Duralumin was co-ordinated in Great Britain from 1911 by the Alloys Research Committee of the Institution of Mechanical Engineers. The 11th report of this committee published in 1921 summarized eight years of work by the National Physical Laboratory NPL . The outstanding result of this work was the development of Y alloy 4 per cent Cu 2 per cent Ni and per cent Mg which retained its strength to moderately high temperatures and was extensively used for pistons and cylinder heads. Y alloy was originally used in the cast form. High Duty Alloys was established in 1928 by Colonel . Devereux to produce variants of Y alloy in the forged condition for aircraft engine use. From these experiments stemmed the RR series of light alloys jointly .
