Second-order and third-order elastic constants of B$_4$C ceramics

The linear and nonlinear elastic properties of B$_4$C boron carbide ceramics have been studied. The second-order elastic constants and other parameters of the theory of elasticity in the linear approximation have been calculated based on the experimentally measured density and velocity values of longitudinal and shear bulk acoustic waves in the samples. The Thurston–Brugger method has been used to determine the third-order elastic constants of B$_4$C. To achieve this, we have measured the relative changes of the longitudinal and shear bulk acoustic wave velocities depending on the uniaxial compression applied to the sample.