Mechanical behavior and material property of low-carbon steel undergoing low-frequency vibration-assisted upsetting

Abstract

The propagation of ultrasonic wave in solids can cause a softening effect during metal deformation, and this concept has been widely exploited in micro-forming. Low-frequency vibration with micro-amplitudes was recently found to have a similar effect on metal deformation. In this study, the effects of low-frequency vibration on the mechanical behavior and microstructure of low-carbon steel DC04 during upsetting deformation was investigated. Vibration-assisted compression test results showed low-frequency vibration had a softening effect, that was proportional to vibration amplitude. Residual softening occurred in all cases during re-yield period after vibration removal. A sectional view of the deformed sample showed that vibration with larger amplitude could exacerbate the deformation of the contact area between the sample and the mold. The internal misorientation of grains in the deformation zone of the compressed sample increased significantly after large vibration treatment, indicating that low-frequency vibration promoted the occurrence of plastic deformation. A softening model considering transfer efficiency was proposed to explain the different performances under the action of small amplitude and large amplitude vibration. The residual softening effect that occurred in this study was an illusion produced by the uneven sample deformation caused by low-frequency vibration.