Integrated Computational Materials Engineering (ICME) and CALPHAD
Integrated Computational Materials Engineering (ICME) is an approach to designing products, the materials they are comprised of and their associated materials processing methods. The article discusses this approach and explains how computational thermodynamics, specifically CALPHAD-based tools like Thermo-Calc, enable the prediction of the thermodynamic properties and phase stability of an alloy under stable and metastable conditions. The article then give several examples showing how the tools are currently being used.
Predicting Heat Treatments for Additively Manufactured Parts
Many additive manufacturing processes subject the material to rapid solidification with multiple subsequent reheat cycles. The effect of these thermal cycles on material properties is not always known. Typically, it does not result in the properties that a similar cast or wrought metal would have. In one study discussed in the article, the Scheil-Gulliver model for solidification in Thermo-Calc in conjunction with the Diffusion Module (DICTRA) was used to explore this issue. The Precipitation Module (TC-PRISMA) predicted the precipitation kinetics of the deleterious delta phase for nominal feedstock compositions, as well as the compositions measured at dendrite boundaries.
Gas Carburizing Highly-Alloyed Steels
Highly-alloyed stainless steels can be gas carburized to increase the surface hardness, as well as to improve the overall mechanical characteristics of the surface. CALPHAD-based tools can be used to identify suitable alloy compositions and heat treat windows, which are optimal for the application prior to testing in the laboratory. In one study, thermodynamic calculations performed with Thermo-Calc and diffusion simulations performed with the add-on Diffusion Module (DICTRA) were used to optimize a carburization heat treatment schedule for their specific steel composition.