Dislocation theory of melting for iron, revisited

The melting point Tm of iron at conditions of the Earth’s inner core boundary (ICB) has been calculated from the dislocation theory of melting in metals. Monte Carlo calculations were used to estimate uncertainties introduced by uncertainty in the geophysical parameters that are used in the calculations. These calculations take into account the effects of pressure at ICB conditions and of possible freezing point depression resulting from dilution of pure iron in the outer core. With this approach Tm of pure e‐Fe at a pressure of 330 GPa and without freezing point depression is 6160±250 K; for a 1000 K freezing point depression it is 6110 K. Tm of pure γ‐Fe is 6060 K, a value that is not significantly different. A possible α’ phase would melt at 5600 K. These values agree with calculated shock wave determinations of Tm. Although calculated Tm of the pure phase is little affected by assumptions about the extent of freezing point depression, the estimated temperature of the inner core boundary is lower by th...