Materials Letters: X (Jun 2020)
Mechanical alloying in the Li-Sn system
Abstract
Li-Sn alloys are of considerable interest in the design of plasma facing systems for nuclear fusion reactors. This letter reports the production of Li-Sn alloys by mechanical alloying, followed by cold pressing. Li atomic concentrations below 25 at.% were studied. Powder morphology during milling evolves from cold welded, rugose powders, to spherical or faceted smoother powders, and finally to thin large discs. Cold-welding and alloying are the predominant mechanisms observed up to 24 h milling. An out of equilibrium distribution of LixSny intermetallic particles with sub-micrometric size forms. Milled powders could be formed into pellets by cold pressing due to its ductility and cold welding behaviour. Contamination free Li-Sn alloys, with 5, 15 and 25 at.% Li, were successfully produced by this method. The main phases identified are β-Sn, Li2Sn5 and LiSn. Phase composition evolves with annealing, with LiSn decrease and Li2Sn5 increase.
