We present a theory of pressure-dependent melting temperature to
describe the physical fact that both cooling and pressurization can
cause the solidification of liquid metal. Based on the Force-Heat
Equivalence Energy Density Principle, an equivalent relationship between
the heat energy variations during cooling and the mechanical work during
pressurization is established as the molten metal solidifies. Then, this
equivalent relationship is applied to develop a pressure-dependent
melting temperature model without any adjustable parameter for metals.
The model reveals the inner relationship between melting temperature,
pressure, the bulk modulus and its first pressure derivative at zero
pressure. The predicted results by our model are in good agreement with
the available experimental data. Moreover, this study provides insights
into the fundamental understanding of quantitative effect of pressure on
melting temperature, which is in contrast to the well-known Lindemann's
and Simon's equations that are both empirical melting temperature
equations. It is worth noting that the melting curve of metals to very
high pressure can be well predicted by our model only needing two
experimental data at low pressures.