Enhancing the resistance to fatigue crack propagation on turbine blades by applying nanotechnology to hot-section surface: A review with nano

Abstract

This review synthesizes recent advances in nanostructured coatings and surface treatments aimed at improving fatigue crack propagation (FCP) resistance in nickel-based superalloys and titanium alloys used in gas turbine hot-section components. Under extreme temperatures and severe thermo-mechanical fatigue (TMF) conditions, FCP remains the dominant life-limiting failure mechanism. Conventional coatings primarily address oxidation and thermal protection, offering limited benefits to mechanical fatigue resistance. In contrast, nanotechnology-driven approaches directly mitigate crack growth through three key paradigms. Nanocrystalline surface layers produced by techniques such as surface mechanical attrition treatment (SMAT) generate ultra-fine grains that suppress persistent slip band formation and promote crack deflection. Nano-multilayer coatings introduce dense interfaces that impede dislocation motion, inducing crack branching and reducing the effective stress intensity range. Nanocomposite reinforcements incorporating hard nanoparticles enhance surface hardness and erosion resistance, delaying crack initiation. Overall, nanostructured layers significantly reduce crack growth rates in the Paris regime, offering a promising pathway to decouple high-temperature stability from structural integrity. Future research should focus on long-term TMF stability and scalable manufacturing for complex turbine geometries. Furthermore, emerging nanotechnology-based smart coatings and nanoscale modeling approaches provide additional opportunities for real-time damage monitoring, self-healing behavior, and enhanced durability under extreme service conditions.