Fast interpolation algorithm for the calculation of thermodynamic property maps of microstructures

摘要

A fast method for the calculation of thermodynamic property mappings of alloy microstructures is presented. It uses surrogate interpolation models instead of the direct CALPHAD calculation of each data point. With the best algorithm, a speed-up of nearly 30 can be achieved compared to the direct method. If repeated calculations of similar microstructures are required, a speed-up of around 300 can even be realized. Different surrogate models have been evaluated. The universal kriging method gives the most accurate results, while polynomial surface response models turn out to generate larger interpolation errors. In order to minimize the number of calculation points of the surrogate interpolation model, the microstructure is classified into similar regions, in which the design points are chosen randomly. The algorithm is applicable independent of alloy composition. Within the paper, we present the application of the algorithm for two single-crystalline nickel-based superalloys.