Study on constitutive behavior of Ti-45Nb alloy under transversal ultrasonic vibration-assisted compression

Ultrasonic vibration technology has been widely applied in plastic forming processes due to its advantages of material properties improvement. In this study, a transverse ultrasonic vibration-assisted compression (TUVC) system with the range of vibration amplitude from 16 to 48 µm is developed to compress the difficult-to-deformation materials. The experiment found that the temperature of the compressed sample with the vibration amplitude of 38 µm arrived at 164 ℃, hence the current constitutive models are deficient for the description of TUVC deformation behavior with the large vibration amplitudes. The results show that the flow stress declines under the coupling action of volume effect and surface effect, especially the amplitude is larger than 38 µm. To accurately depict the constitutive behavior of titanium alloy under TUVC, a hybrid constitutive model considering the difference of softening mechanism was proposed based on crystal plasticity theory, and the predicted curves are in good agreement with experimental results. Finally, the microstructure further revealed the differences of softening mechanism in TUVC, and numerous secondary α phase was precipitated. Consequently, the studies provide an insight into the deformation mechanism of TUVC and promote the application of ultrasonic vibration-assisted forming for the difficult-to-deformation alloy.

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Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2021)