GB652230A - Improvements in or relating to magnesium base alloys - Google Patents

Abstract

A composition for alloying zirconium with magnesium consisting of an intimate fused anhydrous mixture consisting of at least one of the chlorides of barium and strontium, zirconium chloride, with or without halides of "permissible elements," the mixture containing at least 15 per cent of barium chloride or at least 20 per cent of strontium chloride or a mixture of barium and strontium chlorides in amounts equivalent to at least 15 per cent barium chloride reckoning 1 per cent of strontium chloride as equivalent to at least 0.7 per cent of barium chloride, the mixture containing at least 4 per cent of zirconium. The mixture may contain one or more of the chlorides of potassium and sodium, e.g. it may contain at least 15 per cent of zirconium chloride and at least 10 per cent potassium chloride. The mixture may also contain some zirconium fluoride for the purpose of inspissating the chlorides remaining after alloying. A composition formed by reacting the above mixture with molten magnesium may also be used for alloying zirconium with magnesium. This composition consists of an intimate fused mixture having the following phases: (1) a salt phase consisting of barium and/or strontium chlorides and magnesium chloride with or without alkali metal chlorides or calcium chloride and reducible chlorides of "permissible metals," the quantity of which phase is 1-30 per cent by weight of the composition; (2) a phase rich in magnesium or in a "permissible element"; (3) a zirconium rich phase disposed within phase (2) and containing zirconium in a readily alloyable form, the composition being substantially free from fluorine and "zirconium alloying inhibitor elements" and containing at least 5 per cent of zirconium. "Permissible elements" are defined as elements which are incapable of combining with the zirconium dissolved in magnesium to form high melting point compounds which settle out. These elements are chiefly zinc, cadmium, cerium, silver, thallium, thorium, copper, bismuth, beryllium, lead, calcium. "Zirconium alloying inhibitor elements" are elements which do form such high melting point compounds. Specifications 511,137, 624,304, 652,222 and 652,234 are referred to.