How to minimise thermal fatigue in surface multi-treatments and coatings?

A tool is developed to rank surface treated materials with respect to thermal fatigue. It comprises a modelling of the temperature profile in the component and an adaptation of the Coffin-Manson model for surface treatments fatigue. It is used as a performance index and discussed onto several surface treatments and multi-treatments relevant for the protection of steel in aluminium foundry moulds, exposed to thermal fatigue, with some insight in the effect of surface treatments processes on the final result. The model reproduces the well-known capability of duplex PVD nitride onto nitriding to withstand thermal fatigue. Using thermal barrier coatings may also be relevant, but the internal stress must be sufficiently compressive to be resistant to the studied thermal cycles.