Casting and Solidification

The melting temperature of an alloy can be sensitive to its specific chemistry. Handbooks and material data sheets typically only specify a nominal value for the liquidus and solidus temperatures. Even within a material chemistry specification, there can be quite a large range of transformation temperatures. Thermo-Calc can be used to explore the entire chemistry specification range and its effect on solidification behavior.

This plot shows the variation in solidus temperature calculated for 1000 compositions that fall within the alloy 718 specification range. This can be used to understand potential long tail effects in different specification ranges.

Many casting and solidification finite element codes require material property data, such as latent heat, as inputs. Typically, these values are obtained from a handbook or by physically testing the material. Handbook data can be limiting as it typically does not account for heat to heat variations, temperature, and meta-stability, and simply may not exist for every alloy or novel chemistry. With Thermo-Calc, properties such as density, specific heat, and enthalpy can be calculated as a function of composition and temperature, and used to improve finite element modeling. These values can also be calculated under equilibrium (slow cooling) and non-equilibrium (rapid cooling) conditions.

This figure shows the calculated latent heat as a function of temperature during non-equilibrium solidification for a specific heat of alloy 316L. Some handbook values—which are for equilibrium and for an unknown chemistry—are shown for reference.