A Review on Ultrasonic-Assisted Forming: Mechanism, Model, and Process

Abstract

Compared with conventional forming processes, ultrasonic-assisted forming technology with a high frequency and small amplitude can significantly improve the forming quality of materials. Owing to the advantages of reduced forming force, improved surface quality, avoidance of forming defects, and strengthened surface structure, ultrasonic-assisted forming technology has been applied to increasingly advanced forming processes, such as incremental forming, spinning, and micro-forming. However, in the ultrasonic-assisted forming process, there are multiple ultrasonic mechanisms, such as the volume effect and surface effect. The explanation of the effect of ultrasonic vibration (UV) on plastic deformation remains controversial, hindering the development of related technologies. Recently, many researchers have proposed many new theories and technologies for ultrasonic-assisted forming. To summarize these developments, systematic discussions on mechanisms, theoretical models, and forming performances are provided in this review. On this basis, the limitations of the current study are discussed. In addition, an outlook for ultrasonic-assisted forming is proposed: efficient and stable UV systems, difficulty forming components with complex geometry, explanation of the in-depth mechanism, a systematic theoretical prediction model, and multi-field-coupling energy-assisted forming are considered to be hot spots in future studies. The present review enhances existing knowledge of ultrasonic-assisted forming, and facilitates a fast reference for related researchers.

Research on ultrasonic assisted press-fit assembly of small interference fits

“…This type of superposition does not affect the microstructure of the material. 23,24 The UAPA process can be regarded as a combination of upsetting and wire drawing processes. According to the studies of Murakawa and Jin 25 and Yao et al, 20 it is easy to infer that the stress superposition also exists in UAPA process.…”

Achieving High Strength-plasticity of Nanoscale Lamellar Grain Extracted from Gradient Lamellar Nickel

“…The working principle of UADR is that working head exerts a certain amplitude of ultrasonic vibration on metallic material surface along normal direction and simultaneously feeds along the uniaxial direction, which induces normal stress to refine grains and shear stress to elongate grains on the metallic material surface [25][26][27]. During the UADR processing, which is shown in Figure 2, the annealed rod sample rotates at a velocity of 250 r/min, while a steel ball penetrates into sample surface and rolls along axial direction at a velocity of 10 mm/min.…”

Ultrasonic temporary softening and residual hardening

“…As a result, numerous investigators (e.g. [2], [5]- [7]) suggest that ultrasonic vibration induces sufficient heat input to the sample to initiate dynamic annealing, which leads to the reduction of dislocation density. The mechanism of dynamic annealing mainly depends on the stacking fault energy (SFE) of sonicated material.…”