Elektron is the registeredtrademark of a wide range ofmagnesiumalloys manufactured by a British company,Magnesium Elektron Limited.
There are about 100 alloys in the Elektron range, containing from 0% to 9.5% of some of the following elements in varying proportions:aluminium (< 9.5%),yttrium (5.25%),neodymium (2.7%),silver (2.5%),gadolinium (1.3%),zinc (0.9%),zirconium (0.6%),manganese (0.5%) and otherrare-earth metals.[1]
Varying amounts of alloying elements (up to 9.5%) added to the magnesium result in changes to mechanical properties such as increasedtensile strength,creep resistance, thermal stability orcorrosion resistance. Elektron is unusually light and has aspecific gravity of about 1.8 compared with the 2.8 of aluminium alloy, or the 7.9 of steel.[2] Magnesium's relatively lowdensity makes its alloy variants suitable for use inauto racing andaerospace engineering applications.
Elektron orElektronmetall was first developed in 1908 by Gustav Pistor and Wilhelm Moschel at theBitterfeld works of Chemische Fabrik Griesheim-Elektron (CFGE or CFG), the headquarters of which was inGriesheim am Main,Germany.[3][4] The composition of the initial Elektron alloy was approximately Mg 90%, Al 9%, other 1%. At its pavilion at the International Aviation Fair (Internationale Luftschiffahrt-Ausstellung, ILA) inFrankfurt am Main in 1909, CFG exhibited anAdler 75HP engine with a cast magnesium alloy crankcase.[5] Also exhibiting at the 1909 Frankfurt Air Exhibition wasAugust Euler (1868–1957) – owner of German pilot's licence No. 1 – who manufacturedVoisin biplanes under licence inGriesheim am Main. His Voisins with Adler 50 hp engines flew in October 1909.[6]
CFG joined the newly createdIG Farben as an associate company in 1916. During the Allied Occupation afterWorld War I, a Major Charles J. P. Ball, DSO, MC, of theRoyal Horse Artillery was stationed in Germany. He later joined F. A. Hughes and Co. Ltd., which began manufacturing elektron in the UK under licence from IG Farben from around 1923.[7]
CFG merged fully with the IG Farben conglomerate in 1925 along with VersuchsbauHellmuth Hirth (a copper alloy manufacturer), to form another company,ElektronmetallBad CannstattStuttgart. In 1935, IG Farben,ICI and F. A. Hughes and Co. (22% shares) foundedMagnesium Elektron Ltd. ofClifton, Greater Manchester. The company is still manufacturing alloys in 2017.[8][9]
Elektron has been used inZeppelin airships, aircraft, and motor racing applications.
Incendiary bombs using elektron were developed towards the end of the First World War by both Germany (the B-1EElektronbrandbombe orStabbrandbombe) and the UK. Although neither side used this type of bomb operationally during the conflict,Erich Ludendorff mentions in his memoirs a plan to bomb Paris with a new type of incendiary bomb with the aim of overwhelming the city's fire services;[10] this planned raid was also reported inLe Figaro on 21 December 1918.[11] The lightness of elektron meant that a large aeroplane like one of theRiesenflugzeug heavy bombers could carry hundreds of bomblets.[12]
British and German incendiary bombs used extensively duringWorld War II weighed about 1 kg and consisted of an outer casing made of elektron alloy, which was filled withthermite pellets and fitted with a fuse. The fuse ignited the thermite, which in turn ignited the magnesium casing; it burned for about 15 minutes. Trying to douse the fire with water onlyintensified the reaction. It could not be extinguished and burned at such a high temperature that it could penetrate armour plate.[13]
In 1924, magnesium alloys (AZ; 2,5–3,0% Al; 3,0–4,0% Zn) were used in automobile pistons diecast by Elektronmetall Bad Cannstatt, another IG Farben company formed out of Versuchsbau Hellmuth Hirth.
The main engine bearers of theMesserschmitt Bf 109 and theJunkers Ju 87 were made from forged elektron.[14] The air-cooledBMW 801radial aero engine that powered theFocke-Wulf Fw 190 had a fan made of magnesium alloy, very probably elektron.
An advertisement in the German trade paperFlugsport in 1939 claimed that the record-breakingArado Ar 79 aircraft contained 25% by weight of elektron, mostly in theHirth HM 504 A2 4-cylinder inline engine whose crankcase was made of Elektron.[15]
The connectors for the fuel pipes in the engine compartment ofTiger II tanks were originally made of elektron, but they distorted when clamped and were replaced with steel ones.[16]
Siemens-Halske used elektron casings for theirHellschreiber military teleprinter used during WW2.[17]
The prototype 4-seater 1948Planet Satellite had amonocoque fuselage of elektron, a solid elektron keel and wings skinned in elektron, but the keel suffered from stress failures and never reached production.[18]
The bodywork of certain racing cars utilized elektron, including theMercedes-Benz 300 SLR thatinfamously crashed in the1955 Le Mans race, highlighting its flammability.[19]