Energy field assisted metal forming: Current status, challenges and prospects

Authors: H. Li,  L. F. Peng, B. Meng, Z. T. Xu, L. L. Wang, G. Ngaile, M. W. Fu

One of the critical researches in Joint Research Centre (JRC) is developing and employing advanced manufacturing technologies for producing Micro-/Meso-scaled Surface Functional Structures (MSFSSs). The fabrication requirements include high precision, low cost, and good manufacturability. In order to develop and re-innovate suitable processes, uprising technologies using energy field assistance were systematically revisited and analyzed.

Typical high energy-assisted forming technologies viz. electrically-assisted forming (EAF), ultrasonic vibration-assisted forming (UVAF), and electromagnetic forming (EMF), were mainly reviewed from the aspects of process characteristics, material behaviours, numerical modelling, and practical applications. Compared with conventional forming processes, these novel technologies could reduce forming force, improve forming limit, enhance dimensional precision, and decrease forming defects. By using EAF, the dislocation motion could be promoted, the critical temperature for recrystallization and phase transformation could be reduced, and micro-crack healing mechanisms could be stimulated when applying current. UVAF introduced high-frequency loading in materials, so the interface friction was reduced, and acoustic softening of materials was realized, which could significantly improve the surface quality and functional performance of fabricated structures. Time-varying repulsive electromagnetic force could be generated between inductance and materials in EMF, so a high-rate deformation could be imposed in base materials, contributing to the improvement of forming limit and profile accuracy of workpieces. Forming technologies coupling multi-energy fields is promising for the manufacturing of unique and complex parts and structures such as MSFSSs because they exhibit great potential in tailoring the microstructure and properties of materials and improving forming quality and efficiency.