On the determination of the thermal shock parameter of MAX phases: A combined experimental-computational study

Thermal shock resistance is one of the performance-defining properties for applications where extreme temperature gradients are required. The thermal shock resistance of a material can be described by means of the thermal shock parameter RT. Here, the thermo-mechanical properties required for the calculation of RT are quantum-mechanically predicted, experimentally determined, and compared for Ti3AlC2 and Cr2AlC MAX phases. The coatings are synthesized utilizing direct current magnetron sputtering without additional heating, followed by vacuum annealing. It is shown that the RT of both Ti3AlC2 and Cr2AlC obtained via simulations are in good agreement with the experimentally obtained ones. Comparing the MAX phase coatings, both experiments and simulations indicate superior thermal shock behavior of Ti3AlC2 compared to Cr2AlC, attributed primarily to the larger linear coefficient of thermal expansion of Cr2AlC. The results presented herein underline the potential of ab initio calculations for predicting the thermal shock behavior of ionically-covalently bonded materials.

Automated summary

Thermal shock resistance is a crucial property for applications that require extreme temperature gradients. The thermal shock parameter RT is used to describe the resistance of a material. In this study, the thermo-mechanical properties of Ti3AlC2 and Cr2AlC MAX phases were predicted and compared using quantum-mechanical calculations and experiments. Coatings of these materials were synthesized using direct current magnetron sputtering and vacuum annealing. The results showed good agreement between the simulated and experimental RT values for both materials. Comparing the MAX phase coatings, it was found that Ti3AlC2 exhibited superior thermal shock behavior compared to Cr2AlC, primarily due to its larger coefficient of thermal expansion. This study highlights the potential of ab initio calculations for predicting the thermal shock behavior of ionically-covalently bonded materials.