Influence of High-Current-Density Impulses on the Compression Behavior: Experiments with Iron and a Nickel-Based Alloy

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• 作者：E. Demler ; G. Gerstein ; A. Dalinger…
• 关键词：current impulse ; high current density ; nickel alloy ; plasticity ; pure iron
• 刊名：Journal of Materials Engineering and Performance
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：26
• 期：1
• 页码：177-184
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Characterization and Evaluation of Materials; Tribology, Corrosion and Coatings; Quality Control, Reliability, Safety and Risk; Engineering Design;
• 出版者：Springer US
• ISSN：1544-1024
• 卷排序：26

文摘

Difficulties of processing of high strength and/or brittle materials by plastic deformation, e.g., by forging, require to develop new industrial technologies. In particular, the feasible deformation rates are limited for low-ductile metallic materials. For this reason, processes were investigated to improve the deformability in which electrical impulses are to be applied to lower the yield strength. However, owing to the impulse duration and low current densities, concomitant effects always occur, e.g., as a result of Joule heating. Current developments in power electronics allow now to transmit high currents as short pulses. By reducing the impulse duration and increasing the current density, the plasticity of metallic materials can be correspondingly increased. Using the examples of polycrystalline iron and a single-crystal, nickel-based alloy (PWA 1480), current advances in the development of methods for forming materials by means of high-current-density impulses are demonstrated. For this purpose, appropriate specimens were loaded in compression and, using novel testing equipment, subjected to a current strength of 10 kA with an impulse duration of 2 ms. For a pre-defined strain, the test results show a significant decrease in the compressive stress during the compression test and a significant change in the dislocation distribution following the current impulse treatment.