Research On Simulation And Equipment Of Electrically Assisted Wire Drawing Of Metallic Glass

A metallic glass is considered as a new type of metal material with great development due to its advantages of high mechanical strength,high corrosion resistance,and excellent electromagnetic properties.However,the forming and application range of metallic glass wires are limited by its shortcomings of brittleness at room temperature and difficulty in processing.In the forming process of metals,high density pulse current can significantly decrease the deformation stress and improve the elongation.As a novel and energy-saving anufacturing process,electrically assisted wire drawing process has been developed by applying Electroplastic Effect to the metal wire drawing process.And it is a challenging and promising problem whether the electrically assisted wire drawing process can be applied to achieve the high quality and continuous production of metallic glass wires.Therefore,the mechanism of Electroplastic Effect,the equipment and process of electrically assisted wire drawing are studied based on the Zr₅₅Cu₃₀Al₁₀Ni₅ metallic glass in this paper.The details are as follows:Firstly,the finite element simulations of the electrically assisted uniaxial tensile experiments of Zr₅₅Cu₃₀Al₁₀Ni₅are carried out by ABAQUS.It is found that thermal expansion can effectively decrease stress,while thermal softening can effectively improve plasticity in Joule heating effect.The electromigration effect and the Joule heating effect are decoupled by comparing the simulations with the experiments.The results show that,among the Electroplastic Effect,the electromigration effect accounts for about 37.8% while the Joule heating effect accounts for about 62.2%.Secondly,the process of electrically assisted drawing of Zr₅₅Cu₃₀Al₁₀Ni₅ is simulated and analyzed in both single and double die model.The effects of current and drawing parameters on drawing force are studied in the single-die model.The results show that the continuous applied current density should be less than 43 A/mm²,the pulse width should be as small as possible,and the diameter reduction should be less than 15%in the electrically assisted drawing process of Zr₅₅Cu₃₀Al₁₀Ni₅.The simulation results of double-die model show that the current can be evenly distributed on the wires in the structure where the dies acts as the electrodes,which can effectively restrain the electric sparks and improve the surface quality of the wires.The feasibility of reducing forming by double-die drawing is verifiedFinally,based on the simulation analysis,an electrically assisted wire drawing equipment suitable for metallic glass wires is designed.And a die box unit integrated with wire drawing and current application is used to ensure close contact between the wire and the electrodes to solve problems such as electric sparks.A closed-loop path between the pulse power supply and the temperature measuring unit is constructed to realize the temperature control of the sample.A static test shows that the steady-state error of the sample temperature is less than 5?.