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Micromachined structures decoupling Joule heating and electron wind force
Shaojie Gu1, Yasuhiro Kimura2, Xinming Yan2
1Department of Micro-Nano Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8601, Japan. gu.shaojie.e7@f.mail.nagoya-u.ac.jp.
Nature Communications
|July 18, 2024
Summary
Researchers disentangled thermal and athermal effects in electric current treatments using pre-micromachined structures. The electron wind force (EWF) was found to primarily govern microstructural changes, influencing element diffusion and phase transformation in duplex stainless steel.
Area of Science:
- Materials Science
- Physics
- Metallurgy
Background:
- Electric current treatments like electromigration and electroplasticity cause critical microstructural changes in conductive materials.
- The thermal effect (Joule heating) often obscures the athermal effects on these microstructural modifications.
- Understanding athermal effects is crucial for advanced semiconductor and metal processing.
Purpose of the Study:
- To develop a method for effectively disentangling thermal and athermal effects of electric current treatments.
- To investigate the role of the electron wind force (EWF) in microstructural alterations.
- To validate the proposed method using a duplex stainless-steel material.
Main Methods:
- Utilizing pre-micromachined structures to obstruct current flow while maintaining similar thermal history.
- Conducting microstructural characterizations on treated duplex stainless steel.
- Developing a critical formula for determining micromachined structure dimensions.
Main Results:
- The athermal effect, specifically the electron wind force (EWF), was identified as the primary driver of element diffusion and phase transformation.
- Precipitation of sigma phases (Cr-enriched) occurred in micromachined structures, but not in the matrix.
- Directional EWF was shown to disrupt chromium aggregation induced by Joule heating.
Conclusions:
- The proposed method effectively separates thermal and athermal effects in electric current treatments.
- The electron wind force plays a dominant role in microstructural changes, distinct from Joule heating effects.
- The developed technique and formula offer a powerful tool for studying athermal phenomena in materials processing.
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