Thermal conductivity of pressureless-sintered Zr-based amorphous composites

This study investigates the thermal conductivity of pressureless-sintered Zr-based amorphous composites. ZnAl crystal powders and Zr-based amorphous alloy powders were uniformly mixed and compressed into bulk billets, followed by pressureless sintering to produce bulk ZnAl/Zr-based amorphous composites. The structure, thermal stability, and thermal conductivity of the composites were analyzed using x-ray diffraction, scanning electron microscopy, differential scanning calorimetry, and laser flash thermal conductivity testing. Results indicate that the amorphous composites exhibit dense structures, and high-temperature pressureless sintering within the subcooled liquid phase range is an effective preparation method. The stability of the Zr-based amorphous matrix remains unaffected by the addition of ZnAl crystal powders, and no interfacial reaction phases are formed between ZnAl crystals and the amorphous matrix during sintering. Moreover, the amorphous composites demonstrate lower thermal conductivity than the Zr-based amorphous alloys in the temperature range of 298–423 K, suggesting improved thermal insulation. Unlike the Zr-based amorphous alloys, the thermal diffusion coefficient of the composites remains relatively insensitive to temperature, further highlighting their superior thermal insulation properties.