The research objective of this proposal is to test the hypothesis that the skin effect due to electrical current will accelerate the bonding of two metallic materials and therefore, enable an innovative electrically-assisted roll bonding process. If successful, it will reduce process complexity, reduce energy consumption, and reduce chemical wastes in achieving thin metal foils with desired surface finish. One of the many applications is for mini-electrodes and -contacts in bio-implants. Miniaturization of bio-implants is highly desirable in improving patients’ quality of life. Intellectual Merit: We propose a novel process, i.e., electrically-enhanced roll bonding process where a high-density high-frequency electrical current passing through the workpiece during deformation, to increase the bonding strength of metals. It has been reported that electrical current can significantly reduce the deformation force and prolong the maximum elongation. However, the mechanisms are not well understood. The utilization of electrical current has not been incorporated into industrial-purpose manufacturing process due to the concern and equipment requirement associated with the high electrical current density. Nevertheless, the great potential is ideal for the microrolling application due to the nature of small characteristic area. Three fundamental questions are to be addressed in achieving the objectives, i.e., how the electrical current affects the plasticity and residual stress of metals subjected to deformation; how to create an energy-efficient and highly integrated rolling mill to satisfy the need of typical biomedical applications; how to ensure the observability of the microrolling process to implement effective process control. Hereby, the planned research tasks are: (1) Experimental characterization and constitutive modeling of material behavior subjected to mechanical and electrical loading; (2) Multi-physics modeling of micro-rolling process and mill structure, i.e., modeling of mechanical stress, thermal and electro-magnetic fields. (3) In-situ SEM observation of grain boundary under high-current density. The proposed experimental and modeling work will be accomplished through this multi-disciplinary research team specialized in deformation process (Cao, NU) and material structure dynamics (Picard, CMU). Broader Impacts: The project will result in new hybrid processes and new understanding of the effect of current on material deformation, which has puzzled many researchers. The understanding of the effect of electrical current on deformation behavior obtained through this project can be applicable a wide range of deformation-based processes. The collaboration between academic institutions will inspire the innovations and talents needed for U.S. manufacturing companies to remain competitive. The project will provide training to our diversified graduate and undergraduate students through research opportunities, course projects and short courses. The project team will work with middle and high school science teachers in developing simulation models and illustrations for their curriculum and extra-curriculum activities.
|Effective start/end date||4/1/15 → 3/31/19|
- National Science Foundation (CMMI-1463459)
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