Mechanical properties of a Gd2SiO5 single crystal

A Gd2SiO5 single crystal ingot tends to crack during Czochralski growth. In order to perform a stress analysis of the ingot, a complete set of elastic constants of the crystal was measured using ultrasonic pulse method. Critical values of tensile and shear stresses were also measured using the three-point loading test, The critical value of the shear stress in the (010) plane is less than 1/10 of that in other crystallographic planes: and an excess shear stress in the (010) plane is genetated the easiest, This excess stress induces dislocations concentrated in the (100) plane during growth and develops residual stress during the cooling process, giving rise to the occurrence of cracking during the growth as well as during the postprocessing.