Second pressure derivatives of the elastic moduli of copper

The second pressure derivatives of the elastic moduli for polycrystalline copper have been determined. While the value of the second pressure derivative of the longitudinal modulus is zero or very small, that for the shear modulus is ∼6.3×10−10 Pa−1, hence the second pressure derivative of the bulk modulus turns out to be positive, with a value of 8.4×10−10 Pa−1.