Stress-strain spectral response of Eu³⁺/Tb³⁺ doped YAG-ZrO₂ fiber reinforced aluminum matrix composites

Composite materials typically fail due to the accumulation and release of stress during the cyclic loading process of external loads. Therefore, stress-strain monitoring plays a crucial role in the assessment of the lifespan and failure prediction of fiber-reinforced aluminum-based composite materials. However, it is challenging to visually characterize stress and strain in the deformation zone of composite materials. Using the fluorescence properties of rare earth ions for stress-strain detection is a feasible approach. The advantage of this method lies in the rich and sharp fluorescence spectra of rare earth ions, which are easy to observe and are highly sensitive to stress. In this study, Eu³⁺ and Tb³⁺ were selected as luminescent centers and incorporated into YAG-ZrO₂ composite fibers, hereinafter referred to as (YAG:Eu³⁺/Tb³⁺-ZrO₂)_cf These were combined with 2024 aluminum powder through hot pressing and sintering to create (YAG:Eu³⁺/Tb³⁺-ZrO₂)_cf-reinforced aluminum-based composite materials. Dynamic tensile fluorescence sensing was used to characterize the luminescent properties of (YAG:Eu³⁺/Tb³⁺-ZrO₂)_cf -reinforced aluminum-based composite materials under dynamic tensile conditions. Additionally, the change in emission spectrum centroid wavelength with stress was investigated to study the luminescence sensing mechanism of internal stress. The results indicate that with increasing tensile stress, Eu³⁺ displays a systematic red shift in the ⁵D₀-⁷F₁ transition, Tb³⁺ exhibits a consistent blue shift in the ⁵D₄-⁷F₅ transition, while with Eu³⁺ demonstrating higher sensing accuracy. This study provides insights into the development of stress sensor materials based on Eu³⁺ and Tb³⁺.