type: Hooke

references:
  - D.J. Dever,
    Journal of Applied Physics 43(8):3293-3301, 1972,
    https://doi.org/10.1063/1.1661710
    fit to Tab. II (T_min=25ºC, T_max=880ºC)

C_11: 232.1e+9
C_11,T: -4.678e+7
C_11,T^2: -5.762e+4

C_12: 135.9e+9
C_12,T: -1.695e+7
C_12,T^2: 1.555e+3

C_44: 117.0e+9
C_44,T: -2.047e+7
C_44,T^2: -2.814e+2

T_ref: 293.15