Abstract: The automatic and high precision system of RMT-150C was carried to test the mechanical parameters of KDP crystal. Elastic modulus, Poisson ratio, compressive strength and tensile strength were obtained. The results indicate that the elastic modulus in [001] and [100] are 39.25 MPa and 16.82 MPa while the Poisson rations are 0.24 and 0.16 respectively and the KDP is elastic-brittle transversely isotropic material. In addition, the compressive strength and tensile strength in [001] is higher than that in [100], so it is easier to crack in [100] than in [001]. Combined with the stress during growth process, it is found that the cracks are mainly caused by tensile stress, which lays an important foundation for studying the crack damage mechanism and proposing measures in the next step.

Key words: The automatic and high precision system of RMT-150C was carried to test the mechanical parameters of KDP crystal. Elastic modulus, Poisson ratio, compressive strength and tensile strength were obtained. The results indicate that the elastic modulus in [001] and [100] are 39.25 MPa and 16.82 MPa while the Poisson rations are 0.24 and 0.16 respectively and the KDP is elastic-brittle transversely isotropic material. In addition, the compressive strength and tensile strength in [001] is higher than that in [100], so it is easier to crack in [100] than in [001]. Combined with the stress during growth process, it is found that the cracks are mainly caused by tensile stress, which lays an important foundation for studying the crack damage mechanism and proposing measures in the next step.