Magnesium-lithium alloys are among the lowest density metallic materials. Addition of lithium, with a relative density of 0·53, in magnesium reduces the density of the alloy significantly. Furthermore, addition of nearly 11 wt.% lithium converts hexagonal close packed structure of pure magnesium to a body centered cubic lattice, markedly improving formability of the alloy. The development of these alloys, however, had been hampered due to the high reactivity of lithium and magnesium in the molten state and also, due to poor creep resistance and instability of mechanical properties at room temperature. In an attempt to indigenize these ultra light alloys for possible applications in Indian satellite programme, detailed research work was initiated in DMRL. The difficulties associated with producing sound cast ingots have been overcome by controlling melting and casting parameters of these alloys. Extensive work has been done on structure-property correlation of alloys with varying lithium content and minor alloying additions. Based on these work, advanced magnesium-lithium alloys have been developed with improved tensile properties, room temperature stability and creep resistance. Wrought products (plates/sheets) of magnesium-lithium alloy have been supplied to ISAC, Bangalore and are being used in their INSAT-2 programme. This paper describes the systematic studies carried out in the laboratory to indigenize these ultra light alloys.

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Development of ultra light magnesium-lithium alloys

The solubility of carbon in low-nitrogen liquid lithium

The reactions of iron carbides with liquid sodium

An attempt has been made to develop a suitable foundry process for production of highly reactive magnesium—lithium alloy castings. This process would permit the manufacture of shaped castings to co...

casting characteristics of magnesium—lithium alloys

Etude de la cinetique et des mecanismes de propagation du front de penetration du lithium liquide dans un acier a 1% de carbone

Mechanisms involved in decarburization and the fissurization of different carbon steels by liquid lithium were studied. The kinetics of liquid lithium penetration were found to depend strongly on the carbon content of the steel, the shape of cementite precipitates and the temperature and annealing time. The exact nature of the chemical reaction between cementite and lithium is established and a mechanism is proposed for propagation of the cracks.

M. Chemla

Papers

Mechanisms of Carbon Steel Decarburization and Penetration by Liquid Lithium