Fatigue crack path of an Al-Zn alloy reinforced with dispersed zirconium dioxide nanoparticles

Aluminum-zinc (Al-Zn) alloys are widely used in various industries due to their low weight, good mechanical properties, and excellent corrosion resistance. However, their susceptibility to fatigue failure under cyclic loading conditions limits their application in components subjected to dynamic stresses. To improve the fatigue behavior, additions of zirconium dioxide have been used as dispersed particles in the alloy matrix. Zirconium oxide (ZrO2) nanoparticles are characterized by high strength, hardness, and thermal stability. Under stress, ZrO2 nanoparticles change their crystal structure from a tetragonal to a monoclinic. This study investigates the fatigue crack growth behavior of an Al-Zn alloy reinforced with dispersed zirconium oxide (ZrO2) nanoparticles. The influence of ZrO2 nanoparticles on crack initiation, propagation, and the resulting fracture surfaces was examined. The results revealed that the addition of ZrO2 nanoparticles significantly altered the fatigue crack path, leading to improved fatigue resistance compared to the unreinforced alloy.