High Performance Alloys for Extreme Environments
New high-performance alloys for engineering systems with enhanced performance are vital to our society and its sustainable future. Among them, there is an increasing demand on more efficient and environmentally friendly aero-engines that can be addressed by higher operational temperatures. Smart design strategies for new, advanced high performance materials are hence required which can operate in more extreme conditions of temperature and environment while maintaining structural integrity.
Our group focuses on investigating the physical interactions between solutes and crystal defects and providing a fundamental understanding of the structure-chemistry relationship in metallic alloys at the atomic level, by exploiting a framework of high-end microscopy and microanalysis. These continuous interactions of solutes with moving crystal defects created by plastic deformation during service are responsible for the unpredictable microstructural and chemical alterations leading to life-limiting failure, via e.g. creep or fatigue, of safety-critical components in aero-engines.
Understanding how solutes and defects interact will unlock new alloy design strategies and pave the way towards solving complex engineering and material design problems, that limit the operating temperature and hence the efficiency and environmental character of aero-engines. Primary goal is to design alloys that will allow using hydrogen as a fuel, aiming to make true the zero emissions dream. Hence, we bridge engineering problems and materials structure at the near-atomic scale, and translate fundamental knowledge to applied engineering science.
The partitioning of a solute at a crystal defect depends on the type of crystal defect, the deformation conditions, i.e. temperature and stress and the overall alloy composition. Such partitioning results in the plasticity-assisted redistribution of interacting solutes mechanism at the near atomic scale. Hence, local chemical inhomogeneities and undesirable microstructural alterations are promoted that lead to fracture. For instance, partitioning of solutes at defects results in the formation of undesirable topologically close-packed phases or in the dissolution of the main precipitation strengthening phase in superalloys, often followed by recrystallization. Understanding these interactions will enable the development of advanced aerospace alloys that can withstand higher operation temperature and more extreme service conditions leading to greener, hotter and safer aero-engines.