MIM-TBC · Microstructure-Informed Numerical Framework for Predicting the Response of TBC System

Among conventional power generation systems, gas turbine (GT)-based technologies provide the optimal balance between reliability, affordability, and, most importantly, flexibility in the face of a substantial proportion of variable renewable energies (VREs). In response to intermittent VREs, the operational profile of GT will shift towards higher ramp rates, more frequent peak-load/base-load cyclic operations, and a greater number of start-ups which will negatively affect the life cycle of hot components. On the other hand, to enhance efficiency, the turbine inlet temperature should increase from the current 1500℃ to 1800℃, exceeding the temperature limit of high-performance superalloys (1300℃) and imparting the severest thermo-mechanical loading on hot gas path components being coated with indispensable overlay or diffusion type thermal barrier coating (TBC) systems. Owing to the multifaceted and severe consequences of protective coatings failure, research to predict interrelated deformation, chemo-thermo-mechanical degradation and subsequent failure of TBC systems particularly under high-temperature thermal cycling is a top priority. Experimental durability tests, which are primarily based on empirical fitting of coatings mass loss data, are incapable of predicting the lifetime and long-term degradation of a TBC system. In light of the above circumstances, it is extremely beneficial to develop comprehensive modeling techniques that are capable of replacing time-intensive and limited-scope experimental endeavors. Among the different options available, MCrAlY-YSZ (with M being Ni or Co) arises as the most common protective coating system. MIM-TBC project aims at developing a mechanistic and microstructure-sensitive framework for predicting deformation, damage progression, and lifetime of the MCrAlY-YSZ TBC system. Specifically, the framework will be organized to achieve the following specific objectives: O1) A microstructure-sensitive framework for deformation analysis of MCrAlY-based TBC system under thermal cycling O2) Physically-based lifetime prediction of MCrAlY-based TBC system under thermal cycling.