Thermal conductivity and thermal diffusivity of magnesium-lithium alloys

The thermal diffusivity (a) of solid magnesium–lithium alloys with lithium contents XLi = 5, 10, 17, 21, and 25 at. % was measured using a laser flash method in the temperature range of 300–680 K. Based on the experimental results, the thermal conductivity (λ) of alloys was calculated and compared with the literature values for λ of other compositions. The estimated uncertainties of the obtained data were 3.0–3.4 % for λ and 2.0–2.4 % for a. It is shown that the addition of lithium to magnesium reduces significantly its thermal conductivity, with a more pronounced decrease in λ observed as the Li concentration approaches XLi = 32 at. %. Anomalous features in the form of bends in the temperature dependences λ(T) and a(T) were identified for the Mg95Li5 and Mg75Li25 alloys within the temperature range of 310–330 K, similar to the behavior reported for the Mg70Li30 alloy. Using the calculated data and literature sources, the concentration dependences of thermal conductivity for the Mg–Li system were plotted over the composition range XLi = 0–32 at. %.