Verification of electroplastic effect and its mechanism under uniform current density using torsional deformation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03803
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18020:Manufacturing and production engineering-related
• Research Institution: Yokohama National University
• Principal Investigator: MAENO TOMOYOSHI 横浜国立大学, 大学院工学研究院, 准教授 (80505397)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 電気塑性効果 / ジュール発熱 / 変形抵抗 / 軟化

Outline of Final Research Achievements

The electrical plasticity effect, where the flow stress of a metal decreases during plastic deformation with the application of an electric current, has been reported. To investigate the occurrence of this effect, bar torsion tests with minimal current density changes during deformation were performed. A water-cooled torsion testing machine with a current application was constructed, and torsion tests were performed on aluminium, copper, and titanium bar specimens. Tests without temperature rise were achieved for aluminium and copper, and no change in flow stress due to the current application was observed. For a titanium alloy, a temperature rise due to Joule heating occurred. Still, a comparison of the results with and without current, considering the temperature effect, showed that the decrease in yield stress observed in the titanium alloy was mainly due to the temperature rise caused by Joule heating.

Free Research Field

塑性加工

Academic Significance and Societal Importance of the Research Achievements

アルミニウム，銅，数十 A/mm2以下の電流印加ではジュール発熱による温度上昇や電流密度の集中を抑制すると，明瞭な変形抵抗の変化は生じないことが分かった．つまり，電気塑性効果は生じないことが分かった．また，温度上昇を抑制することが難しい電気抵抗の高いチタンにおいても，同様の電流印加においては変形抵抗の変化は生じるものの，そのほとんどはジュール発熱による温度上昇による軟化であることが，変形抵抗変化の比較およびその変化速度からわかった．