First Principles Simulation of Microstructures for Metals/Alloy Materials in Fuel Cell

The metal/alloy materials have been widely used in fuel cell applications. One of these materials is austenitic steel, which can be used as the interconnector or bipolar plate. The microstructures are elucidated through microscopy observation combined with first principle calculations. It was noted that, in the high nitrogen austenitic steel, there were short-range ordered structures formed through nano-scale clusters. The simulation of such clusters was conducted thereby, and the formation features were analyzed to understand the atomic structures and phase stability. The cluster structure is affected by both the local lattice distortion around the cluster and the Coulombic interaction in the cluster. It was suggested that the stabilization of the metastable phase is mainly a chemically driven mechanism by Cr and N atoms forming short-range ordered clusters.