# On the stochastic phase stability of Ti2AlC-Cr2AlC

## TL;DR

This paper uses a Bayesian CALPHAD approach guided by first-principles calculations to evaluate the phase stability of Ti2AlC-Cr2AlC, incorporating uncertainties and aligning well with experimental data, aiding future MAX phase design.

## Contribution

It introduces a novel first-principles-guided Bayesian CALPHAD method to assess phase stability in MAX phases, accounting for uncertainties in calculations and experiments.

## Key findings

- Good agreement with previous experimental phase stability data
- Demonstrates the method's potential for exploring other MAX systems
- Provides insights into synthesis routes for new MAX phases

## Abstract

The quest towards expansion of the MAX design space has been accelerated with the recent discovery of several solid solution and ordered phases involving at least two MAX end members. Going beyond the nominal MAX compounds enables not only fine tuning of existing properties but also entirely new functionality. This search, however, has been mostly done through painstaking experiments as knowledge of the phase stability of the relevant systems is rather scarce. In this work, we report the first attempt to evaluate the finite-temperature pseudo-binary phase diagram of the Ti2AlC-Cr2AlC via first-principles-guided Bayesian CALPHAD framework that accounts for uncertainties not only in ab initio calculations and thermodynamic models but also in synthesis conditions in reported experiments. The phase stability analyses are shown to have good agreement with previous experiments. The work points towards a promising way of investigating phase stability in other MAX Phase systems providing the knowledge necessary to elucidate possible synthesis routes for MAX systems with unprecedented properties.