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Title: High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness

Abstract

Electrically driven rapid vaporization of thin metallic foils can generate a high pressure which can be used to launch flyers at high velocities. Recently, vaporizing foil actuators have been applied toward a variety of impulse-based metal working operations. In order to exercise control over this useful tool, it is imperative that an understanding of the effect of characteristics of the foil actuator on its ability for mechanical impulse generation is developed. Here, foil actuators made out of 0.0508 mm, 0.0762 mm, and 0.127 mm thick AA1145 were used for launching AA2024-T3 sheets of thickness 0.508 mm toward a photonic Doppler velocimeter probe. Launch velocities ranging between 300 m/s and 1100 m/s were observed. In situ measurement of velocity, current, and voltage assisted in understanding the effect of burst current density and deposited electrical energy on average pressure and velocity with foil actuators of various thicknesses. For the pulse generator, geometry, and flyer used here, the 0.0762 mm thick foil was found to be optimal for launching flyers to high velocities over short distances. Experimenting with annealed foil actuators resulted in no change in the temporal evolution of flyer velocity as compared to foil actuators of full hard temper. A physics-basedmore » analytical model was developed and found to have reasonable agreement with experiment.« less

Authors:
; ;  [1]
  1. Department of Materials Science and Engineering, The Ohio State University, 2041, College Road, Columbus, Ohio 43210 (United States)
Publication Date:
OSTI Identifier:
22308831
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ACTUATORS; ANNEALING; COMPARATIVE EVALUATIONS; CONTROL; CURRENT DENSITY; DOPPLER EFFECT; ELECTRIC POTENTIAL; EVAPORATION; FOILS; METALS; PRESSURE RANGE MEGA PA 10-100; PULSE GENERATORS; STRAIN RATE; THICKNESS; VELOCIMETERS; VELOCITY

Citation Formats

Vivek, A., E-mail: vivek.4@osu.edu, Hansen, S. R., and Daehn, Glenn S.. High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness. United States: N. p., 2014. Web. doi:10.1063/1.4884647.
Vivek, A., E-mail: vivek.4@osu.edu, Hansen, S. R., & Daehn, Glenn S.. High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness. United States. doi:10.1063/1.4884647.
Vivek, A., E-mail: vivek.4@osu.edu, Hansen, S. R., and Daehn, Glenn S.. 2014. "High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness". United States. doi:10.1063/1.4884647.
@article{osti_22308831,
title = {High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness},
author = {Vivek, A., E-mail: vivek.4@osu.edu and Hansen, S. R. and Daehn, Glenn S.},
abstractNote = {Electrically driven rapid vaporization of thin metallic foils can generate a high pressure which can be used to launch flyers at high velocities. Recently, vaporizing foil actuators have been applied toward a variety of impulse-based metal working operations. In order to exercise control over this useful tool, it is imperative that an understanding of the effect of characteristics of the foil actuator on its ability for mechanical impulse generation is developed. Here, foil actuators made out of 0.0508 mm, 0.0762 mm, and 0.127 mm thick AA1145 were used for launching AA2024-T3 sheets of thickness 0.508 mm toward a photonic Doppler velocimeter probe. Launch velocities ranging between 300 m/s and 1100 m/s were observed. In situ measurement of velocity, current, and voltage assisted in understanding the effect of burst current density and deposited electrical energy on average pressure and velocity with foil actuators of various thicknesses. For the pulse generator, geometry, and flyer used here, the 0.0762 mm thick foil was found to be optimal for launching flyers to high velocities over short distances. Experimenting with annealed foil actuators resulted in no change in the temporal evolution of flyer velocity as compared to foil actuators of full hard temper. A physics-based analytical model was developed and found to have reasonable agreement with experiment.},
doi = {10.1063/1.4884647},
journal = {Review of Scientific Instruments},
number = 7,
volume = 85,
place = {United States},
year = 2014,
month = 7
}
  • Dissimilar joining of sheet aluminum AA6061-T4 to cast magnesium AM60B was achieved by vaporizing foil actuator welding (VFAW). Three input energy levels were used (6, 8, and 10 kJ), and as a trend, higher input energies resulted in progressively higher flyer velocities, more pronounced interfacial wavy features, larger weld zones, higher peel strengths, and higher peel energies. In all cases, weld cross section revealed a soundly bonded interface characterized by well-developed wavy features and lack of voids and continuous layers of intermetallic compounds (IMCs). At 10 kJ input energy, flyer speed of 820 m/s, peel strength of 22.4 N/mm, andmore » peel energy of 5.2 J were obtained. In lap-shear, failure occurred in AA6061- T4 flyer at 97% of the base material’s peak tensile load. Peel samples failed along the weld interface, and the AM60B-side of the fracture surface showed thin, evenly-spaced lines of Al residuals which had been torn out of the base AA6061-T4 in a ductile fashion and transferred over to the AM60B side, indicating very strong AA6061-T4/AM60B bond in these areas. Furthermore, this work demonstrates VFAW’s capability in joining dissimilar lightweight metals such as Al/Mg, which is expected to be a great enabler in the ongoing push for vehicle weight reduction.« less
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  • Plasma-assisted molecular beam epitaxy (PAMBE) growth of ultra-thin Al{sub 0.2}Ga{sub 0.8}N/GaN heterostructures on Si(111) substrate with three buffer thickness (600 nm/400 nm/200 nm) have been reported. An unique growth process has been developed that supports lower temperature epitaxy of GaN buffer which minimizes thermally generated tensile strain through appropriate nitridation and AlN initiated epitaxy for achieving high quality GaN buffer which supports such ultra-thin heterostructures in the range of 10-15Å. It is followed by investigations of role of buffer thickness on formation of ultra-thin Al{sub 0.2}Ga{sub 0.8}N/GaN heterostructure, in terms of stress-strain and threading dislocation (TD). Structural characterization were performedmore » by High-Resolution X-Ray Diffraction (HRXRD), room-temperature Photoluminescence (RT-PL), High Resolution Transmission Electron Microscopy (HRTEM) and Atomic Force Microscopy (AFM). Analysis revealed increasing biaxial tensile stress of 0.6918 ± 0.04, 1.1084, 1.1814 GPa in heterostructures with decreasing buffer thickness of 600, 400, 200 nm respectively which are summed up with residual tensile strain causing red-shift in RT-PL peak. Also, increasing buffer thickness drastically reduced TD density from the order 10{sup 10} cm{sup −2} to 10{sup 8} cm{sup −2}. Surface morphology through AFM leads to decrease of pits and root mean square value with increasing buffer thickness which are resulted due to reduction of combined effect of strain and TDs.« less