This study uses a T-type specimen to explore how electric pulses accelerate grain growth in magnesium 

BUSAN, South Korea, Dec. 23, 2025 — Electropulsing treatment (EPT) is an advanced technology for quickly heating metal materials. This highly energy-efficient and environmentally friendly process uses a pulsed current—called an “electropulse”—to achieve unique effects like electroplasticity and electropulsing anisotropy. Compared to traditional furnace heat treatment (FHT), it enables rapid microstructural changes in alloys, likely due to athermal effects that go beyond the impact of Joule heating.

Recent scientific attempts to identify these athermal contributions have focused on directly comparing EPT and FHT at the same temperatures. However, these methods are prone to substantial experimental errors.

In a new study, a Korean research team led by Professor Taekyung Lee—from the School of Mechanical Engineering at Pusan National University and head of the Metal Design & Mechanics (MEDEM) Lab—used a specialized “T-shaped” magnesium sample to separate standard heating effects from EPT’s additional athermal effects. Their findings were released online and recently published in the journal on December 8, 2025.

Prof. Lee emphasizes the novelty of their work, “Our innovative T-type specimen methodology separates the current and heat transfer paths within a single specimen subjected to EPT. This pioneering methodology is contrasted by the conventional method that compared two different specimens: one with EPT and the other with FHT at a similar temperature. This traditional methodology possesses lots of inherent limitations. On the other hand, the T-type specimen methodology allows for the independent analysis of thermal and athermal effects of EPT within a single specimen.”

By precisely controlling the electric current in a pre-twinned AZ31 magnesium alloy sample, the team created two regions in the same sample that reached nearly identical temperatures—though only one carried current. The current-carrying region exhibited stronger strain-induced boundary migration, faster grain growth, removal of twin boundaries, fewer low-angle grain boundaries, dislocation annihilation, and softening compared to the region heated solely by conduction. This confirms that EPT speeds up microstructural changes more than heat alone can explain.

The team validated their results with finite element analysis, which confirmed electric current was restricted to a single beam and accurately replicated the curved thermal pattern observed at the beam intersection in the T-type specimen.

Prof. Lee discusses the long-term impact of their innovative technology, “Measuring the athermal effect without Joule heat, or thermal effect, in the EPT process has long been a major challenge in academia. The developed methodology can help researchers understand the physical principles governing EPT. It is, therefore, expected to become a core standard measuring technology for advancing high-efficiency and eco-friendly forming techniques—known as electrically-assisted forming—for various metallic materials using electropulses.”

Overall, the T-type specimen approach outlined in this study provides a robust framework for separating EPT’s thermal and athermal effects at the macroscale, offering an essential tool to clarify their respective roles in EPT-induced microstructures and mechanical properties.

Reference
Original paper title: Validating the athermal contribution of electropulsing treatment utilizing T-type Mg specimen
Journal: Journal of Magnesium and Alloys
DOI: 

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