Elastic constants of monocrystal iron from 3to500K

Resonant ultrasound spectroscopy was used to measure the monocrystal elastic constants of iron over a temperature range of 3–500K. All the moduli behave normally as a function of temperature and are well described by the semiempirical Einstein-oscillator model. Values at 300K are bulk modulus=166.2±0.9GPa; shear constant C′=(C11−C12)∕2=48.15±0.9GPa; shear constant C44=115.87±0.17GPa. The Poisson ratio (ν100) is 0.3679±0.0005. Representation surfaces of Young’s and torsion moduli are presented. The Debye temperature (θD) is 476.3K as calculated from 3K measured elastic constants. A thermodynamic Grüneisen parameter γth=1.65 is calculated. The temperature dependence of the internal friction associated with C′ is very different from that associated with C44. Possible reasons for this difference are suggested.