利用超声脉冲回波重合法测定铌酸锂单晶弹性常数CijE和CijD

本文从基本的压电Christoffel方程出发导出三角晶系3m点群压电晶体弹性常数的表示式。并采用10MHz射频超声脉冲回波重合法测量了沿LiNbO₃不同对称方向传播的声速,结合e_ij和ε_ij⁵给出了LiNbO₃全部弹性常数C_ij^E和C_ij^D。它们是C₁₁^E=19.8 关键词：

THE ELASTIC CONSTANTS CijE, AND CijD, OF LiNbO3 DETERMINED BY THE ULTRASONIC "PULSE ECHO OVERLAP METHOD"

Based on the fundamental piezoelectric Christoffel's equation, we derived the expression of the elastic constants for piezoelectric crystal with trigonal symmetry point group 3 m. The ultrasonic wave velocities in LiNbO₃ crystal, propagating along different crystallographic directions, are determined by the "pulse echo overlap method". The. carrier frequency of rf pulse is 10 MHz. The Values of the secondorder elastic constants C_ij^E and C_ij^D for LiNbO₃ crystal are obtained as follow: C₁₁^E = 19.89, C₁₂^E = 5.25, C₁₃^E = 7.81, C₁₄^E = 0.96, C₃₃^E = 25.44, C₄₄^E = 6.10, C₆₆^E=7.32×10¹⁰N/m²·C₁₁^D = 21.51, C₁₂^D= 3.65, C₁₃^D = 7.91, C₁₄^D=-1.41, C₃₃^D = 26.10,C₄₄^D = 9.62, C₆₆^D = 8.93×10¹⁰N/m².