The microstructural evolution and ultrasonic guided wave transduction performance of annealed magnetostrictive (Fe83Ga17)99.9(NbC)0.1 thin sheets

Based on the ultrasonic guided wave detection technique, the effects of the annealing process on the microstructures, properties, and ultrasonic guided wave transduction performances of (Fe ₈₃Ga ₁₇) _99.9(NbC) _0.1 thin sheets with thicknesses ranging from 0.06 mm to 0.15 mm for magnetostrictive guided wave sensors in non-destructive testing were investigated. The results demonstrated that in contrast to the texture formed when annealing under an Ar atmosphere, the {1 0 0} 〈0 0 1〉 texture formed in the recrystallized Fe-Ga thin sheets annealed with a flowing Ar/H ₂ gas mixture, resulting in a saturation magnetostriction of 145 ppm. This might have been related to the influence of the strain recrystallization rate, stored energy, and surface energy. The proposed magnetostrictive guided waves could be used for inspection using the thin sheets. In particular, the thin sheet annealed at 1200 °C for 2 h exhibited excellent guided wave sensing characteristics. This was mainly attributed to the formation of a cubic texture and the value of (dλ/d H) _max corresponded to a lower-bias magnetic field. This demonstrated that a proper annealing treatment improved not only the texture but also the sensitivity for guided wave detection. Therefore, this work demonstrated the prospects of applying (Fe ₈₃Ga ₁₇) _99.9(NbC) _0.1 thin sheets for ultrasonic guided wave detection.