Iron under conditions close to the α-γ-∈ triple point

The stability domains and equations of state of alpha-Fe, is an element of-Fe, and gamma-Fe have been measured using X-ray diffraction under conditions close to their triple point: 7 <= P <= 20 GPa and 480 <= T <= 820 K. Special attention was paid to ensure the hydrostatic compression of the sample, which was a single crystal at start. Narrow alpha-gamma and alpha-is an element of coexistence domains were observed, while the gamma-is an element of transformation appeared sluggish. The triple point is measured at 8.7 +/- 1.0 GPa and 750 +/- 30 K. Anharmonic effects are evidenced in the equation of state of is an element of-Fe and partly reproduced using ab initio molecular dynamics simulations. Published by AIP Publishing.