Thermal conductivity of Al-Gd-TM glass-forming alloys
(Institute of Metallurgy, Ural Branch, Russian Academy of Science, Amundsena str., 101, Ekaterinburg 620016, Russia)
Abstract: Thermal diffusivity, specific heat capacity and thermal conductivity of Al86Gd6TM8 (TM = Cu, Ni, Co, Fe, Mn, Cr, Ti, Zr, Mo, Ta) glass-forming alloys in the temperature range of 300-880 K were determined by laser flash method. The temperatures of endothermic and exothermic reactions of the alloys were determined by differential scanning calorimetry method. The alloys were prepared by conventional arc-melting technique under helium atmosphere. All the alloys studied exhibit strong supercooling of the liquidus temperatures up to 80 K, which indicates their good glass-forming ability. The specific heat capacity of the alloys achieves the Dulong–Petit’s value in the temperature range of 350-550 K except Al86Cr8Gd6 and Al86Zr8Gd6 compositions. The values of both thermal diffusivity and thermal conductivity of the alloy studied are significantly lower than those for pure aluminum. It is found that embedding 14% (mole fraction) of transition elements (Gd+ТM) in the aluminum matrix leads to significant decrease in the absolute magnitudes of both thermal diffusivity and thermal conductivity in crystalline state. The thermal conductivity of glass-forming Al86Gd6TM8 alloys is strongly affected by directed chemical bonding between alloy components.
Key words: Al-based alloys; thermal properties; specific heat capacity; thermal conductivity; thermal diffusivity