High-stability SrAl2O4:Eu2+ ultrasonic-induced luminescent material with trap-level engineering for pre-excitation-free nondestructive testing

High-Stability USL: SAO:Eu needs no UV radiation, cutting external effects and boosting practical ease and accuracy. • USL modulation: TL and Sm/Dy/Tm doping proved trap depth and carrier density dictate USL intensity. • Non-destructive testing: SAO:Eu USL enables a structural defect detection simpler than conventional ultrasonic testing. Ultrasonic-induced luminescence (USL), as a novel type of mechanically stimulated luminescence phenomenon, has attracted widespread attention in the fields of materials science and engineering in recent years. Currently reported USL materials suffer from poor stability, and most require UV excitation. In this study, we report a highly stable SrAl 2 O 4 :Eu 2+ material that does not require pre-excitation by a UV lamp. This material exhibits excellent stability in cyclic testing. By combining USL measurements at different pre-treatment temperatures with thermoluminescence testing, and by introducing different activating ions, we establish a close relationship between USL and the carrier density in the traps. Furthermore, a novel structural defect detection method was designed based on the USL properties of this material, offering greater simplicity and convenience compared to traditional ultrasonic testing. This study not only delivers a material with high stability for USL but also introduces a novel paradigm for industrial nondestructive testing.