Genetic alloy design based on thermodynamics and kinetics

Abstract

A theory-guided computational approach for alloy design is presented. Aimed at optimising the desired properties, the microstructure is designed and an alloy composition optimised accordingly, combining criteria based on thermodynamic, thermokinetic and mechanical principles. A genetic algorithm is employed as the optimisation scheme. The approach is applied to the design of ultra-high strength stainless steels. Three composition scenarios, utilising different strengthening precipitates (carbides, Cu and NiAl/Ni₃Ti), are followed. The results are compared to a variety of existing commercial high-end engineering steels, showing that the design strategy presented here may lead to significant improvements in strength beyond current levels.

Keywords:

• alloy design
• ultra-high strength
• stainless steel
• precipitate
• thermodynamics
• kinetics
• genetic algorithm

Acknowledgments

This research was carried out under project number MC5.04192 within the framework of the Research Program of the Materials Innovation Institute M2i (www.m2i.nl), the former Netherlands Institute for Metals Research. The authors thank Dr P. Morris from Corus UK (Sheffield) for the helpful discussions.