Heat treating is the controlled application of time, temperature and atmosphere to produce a predictable change in the microstructure of a material to achieve desired material properties. However, alloys are complex systems where the microstructure and properties depend on both the processing conditions and chemical composition. Variations in heat-to-heat composition, particularly in terms of minor elements, or the extent of inhomogeneity arising from solidification affect properties and processing windows. When these data are not available, Thermo-Calc can be used to fill the gaps and make predictions of material behavior throughout the material’s life cycle as a function of composition, temperature and time.

Predict a Wide Range of Materials Property Data

  • Thermophysical properties: Specific heat, enthalpy, heat capacity, heat of formation, density, coefficient of thermal expansion, viscosity (of liquid), surface tension (of liquid), interfacial energy, thermal conductivity and electric resistivity
  • Kinetic properties: Diffusion coefficients, atomic mobility
  • Mechanical properties: Yield strength, hardness
  • Properties related to equilibrium and non-equilibrium solidification: Liquidus, solidus, incipient melt temperatures, freezing range, fraction solid curves, solidification path, fraction eutectic, microsegregation, partition coefficients, latent heat, shrinkage, susceptibility to hot tearing and more
  • Properties specific to steel: A1 and A3 temperatures, martensite start temperature, martensite fractions, and kinetics of pearlite and bainite formation.

Gain Insight into Materials Processing

Thermo-Calc can simulate the effects of different types of heat treatment – such as homogenization, aging, quenching, surface hardening, stress relief and post-weld heat treatment – to predict the phases/microstructure that form.

Solidification and homogenization

  • Determine homogenization temperature
  • Predict time needed to homogenize

Aging and precipitation

  • Generate TTT diagrams for specific chemistries
  • Determine solvus temperatures of precipitates (i.e., gamma prime)
  • Predict critical phase transformation temperatures (i.e., beta transus, A1, A3)
  • Calculate precipitate volume fraction and size distribution as a function of time
  • Predict stable/metastable precipitation

Surface hardening

  • Calculating furnace activities and chemical potentials based on gas ratios
  • Predict case-depth profiles and precipitate formation during carburization, nitridation, carbonitriding
  • Determine type and amount of carbides