The physical properties of transparent Y3Al5O12: Elastic modulus at high temperature and thermal conductivity at low temperature

We report experimental studies on the physical properties of transparent single and polycrystalline Y3Al5O12 (YAG) used for laser materials or arc tubes for lamps. The elastic modulus and thermal conductivity of the YAG polycrystal were measured. The Youngʹs modulus of the YAG polycrystal was 308 GPa at room temperature and decreased to 264 GPa at 1400 °C. Thermal conductivity increased with increasing grain size at temperatures below 150 K and was almost independent of grain size at higher temperatures. The thermal conductivity of the YAG polycrystal for a grain size of 7.5 μm was 1.1 W/cm K at 37 K, about seven times lower than that of the single crystal.