Plastic workability of pure lithium.

Lithium possesses a wide spectrum of industrial uses. However, lithium is an immature metal with regard to the field of materials engineering. Accordingly, the tensile test as well as plastic workability measurements were carried out at room temperature. The results obtained are yield stress: 0.4 MPa and elongation to rupture: 28%. Since lithium is a very ductile metal, it can therefore be made thinner by rolling. During the rolling operation, lithium plate “work softening” happened after the work hardening. It is thought that the softening is due to the dynamic recrystallization that comes from the heat energy accumulated by the rolling. The applied stress-time to rupture data for pure lithium determined at room temperature. The grain boundary sliding were observed in the creep ruptured specimens. Next, microvickers hardness measurements were also carried out. At low temperatures the hardness increased with decreasing temperature. The increase was sharper in the lithium and the temperature at which the increase start was about 0.3 T/Tm (Tm: melting temperature). This value is higher than 0.1 T/Tm of iron or bcc refractory metals. Superior deformability of lithium in the liquid nitrogen were confirmed by torsion and bending tests.