Magnesium Elektron, Inc.

Other

Luxfer Group Limited

John F King

Stephen L Bradshaw

William Unsworth

Paul Lyon

Ismet Syed

Hossein Karimzadeh

Kevin Nuttall

A magnesium base alloy for high pressure die casting (HPDC), providing good creep and corrosion resistance, comprises: at least 91 weight percent magnesium; 0.1 to 2 weight percent of zinc; 2.1 to 5 percent of a rare earth metal component; 0 to 1 weight percent calcium; 0 to 0.1 weight percent of an oxidation inhibiting element other than calcium (e.g., Be); 0 to 0.4 weight percent zirconium, hafnium and/or titanium; 0 to 0.5 weight percent manganese; no more than 0.001 weight percent strontium; no more than 0.05 weight percent silver and no more than 0.1 weight percent aluminum; any remainder being incidental impurities. For making prototypes, gravity (e.g. sand) cast and HPDC components from the alloy have similar mechanical properties, in particular tensile strength. The temperature dependence of the latter, although negative, is much less so than for some other known alloys.

Magnesium alloys

Magnesium alloys for castings having good tensile properties at both ambient and high temperatures and good resistance to creep contain 1.5-10% of yttrium or an yttrium/heavy rare earths mixture and 1-6% of neodymium or a neodymium/lanthanum/praseodymium mixture. The alloys may be heat treated to improve their properties.

A magnesium alloy contains the following additives: A1 1-9%, Zn 0-4%, Sn 0.1-5%, Mn 0-1%. It is useful as an anode in cells operating with a salt water electrolyte, especially in batteries powering equipment for deep-sea use in which a pulsed power source is required.

Primary electric cell having magnesium alloy anode

A magnesium alloy for casting contains from 2 to 10% of zinc and from 0.5 to 5% of copper as essential constituents, aluminium being substantially absent. The alloy as cast has a fine grain size, making a grain refinement step unnecessary and has favorable mechanical properties, especially after heat treatment. Other constituents such as up to 2% manganese can be added to improve particular properties.

A magnesium-based alloy for casting contains at least 88% magnesium, 1.6-3.5% silver, 0.1-2.3% of rare earth metals comprising at least 60% neodymium, 0-2.3% thorium and 0.1-2.5% yttrium. When no more than 0.5% of yttrium is present the minimum amount of thorium is given by the equation ##EQU1## Other elements may be present to improve the alloy properties.

Magnesium alloys having favorable tensile properties contain silver, copper and neodymium. The alloys are subjected to a solution heat treatment followed by ageing to give optimum properties.

Magnesium alloys having favorable mechanical properties at high temperatures contain silver, neodymium and thorium, the permissible content of neodymium varying inversely according to the content of the thorium. The alloys are subjected to solution heat treatment followed by ageing to give optimum properties.

Magnesium alloys having improved high-temperature properties, especially improved resistance to creep, contain from 1.25 to 3.0% silver, 0.5 to 2.5% of rare metals including at least 60% neodymium and from 2.5 to 7.0% thorium. Optimum properties are obtained by high-temperature solution treatment followed by aging at a lower temperature.

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Bury, United Kingdom

John F King