Electromechanical performance evolution of PZT, PMN-PT, and 1–3 piezoelectric composites at cryogenic temperature

Cryogenic ultrasonic testing technology has a critical potential application in aerospace, deep-space exploration, and nuclear fusion reactors. Ultrasonic transducers are the key components of the ultrasonic testing system. The performance of these transducers is fundamentally determined by the electromechanical response of piezoelectric materials. While the performance of piezoelectric materials at room temperature has been extensively studied, their electromechanical performance at cryogenic temperature of piezoelectric materials (e.g., PZT, PMN-PT, and 1–3 piezoelectric composites) remains unclear. This study systematically investigates the evolution of electromechanical properties of PZT-5, PMN-PT, and 1–3 composites from 292 down to 52 K. By employing the impedance spectroscopy method, key parameters, including the piezoelectric coefficient, electromechanical coupling coefficient, and elastic moduli, are quantitatively characterized. The results reveal that PZT-5 exhibits exceptional frequency stability, with its resonance frequency decreasing by 3.8%, while PMN-PT and 1–3 composites show frequency increases of 6.1% and 17.1%, respectively. Additionally, PZT-5 demonstrates elastic softening (elastic coefficient ΔC33D=−4.3%), in sharp contrast with the hardening behavior observed in PMN-PT (+8.1%) and 1–3 composites (+18.3%). Furthermore, PZT-5 demonstrated exceptional electromechanical coupling stability under cryogenic temperature, showing only a minimal 1.1% variation in coupling coefficient (Δkt). The dielectric constants and piezoelectric coefficients of all three materials exhibit a declining trend as temperature decreases, primarily attributed to the domain wall freezing effect under cryogenic conditions. These findings provide the basis and reference for transducer material selection and design optimization in cryogenic ultrasonic testing.