Project 6: Evolution of mechanical properties of coating systems during exposure at high temperature

M.Sc. Ahmed Eshnaiwer (3^rd cohort), 
M.Sc. Jurica Filipovic (1^st cohort) 

Supervisors: Prof. Matthias Oechsner, PD Matthias Galetz

MatCom-ComMat aims to advance coating technologies through the implementation of polymer-derived ceramics (PDCs) as high-performance thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs). This strategy enables the deployment of refractory alloys in turbine engine applications as a viable alternative to conventional nickel-based superalloys, thereby facilitating operation at temperatures exceeding 1300 °C and significantly enhancing overall engine efficiency.

A critical prerequisite for this development is a comprehensive understanding of the failure mechanisms governing coated material systems under extreme service conditions, including high-temperature exposure, corrosive environments, and cyclic mechanical loading. Such insight is essential to ensure reliability and long-term performance.

The primary objective of Project 6 is to establish a robust and predictive framework for evaluating failure mechanisms and load-bearing capacity in intermetallic phases formed on diffusion-coated, refractory-based substrates. These coated substrates will be developed through close collaboration with Projects 7 and 8. The coating system will be further enhanced by the application of PDC-based TBC/EBC layers, developed in cooperation with Projects 1 and 2, resulting in an integrated, multi-layered coating architecture.

In addition, this project includes a dedicated work package on advanced modeling and simulation. This effort focuses on predicting failure mechanisms and phase transformations within intermetallic coating systems, as well as elucidating the relationship between coating architecture, interfacial properties, and crack initiation and propagation within the bond coat.

Preliminary work in Project 6.1 has investigated the mechanical behaviour and failure mechanisms of aluminum-coated pure molybdenum substrates. This includes detailed modeling of phase formation and interdiffusion processes within the intermetallic coating layers. Building on these findings, future research will shift toward higher-alloy refractory substrates with enhanced creep resistance. This progression represents a key step toward the development of a material system with sufficient durability and lifetime performance to qualify as a viable MatCom-ComMat candidate for high-temperature turbine applications.