The University of Tokyo Graduate School Frontier Science researchers have made a significant breakthrough in understanding the deformation mechanisms of multi-element alloys at high temperatures, which could pave the way for the development of new materials designed for high temperature applications in fields such as aerospace and nuclear energy.

 

Refractory complex concentrated alloys (RCCAs), which are created by mixing high-melting-point metals, has attracted significant attention due to their excellent high temperature performance. Unlike traditional alloys that typically feature one dominant element, RCCAs explore a wide range of compositions, which allows to explore the vast number of compositions. Researchers have made significant efforts to explore these combinations, aiming to discover new materials that can withstand higher temperatures than current temperature limits.

 

Assistant Professor Sae Matsunaga, along with undergraduate student Osamu Shimizu, graduate students Shaoji Liang and Yu-Nien Shen, and Professor Yoko Yamabe-Mitarai, created four different alloys using iridium, rhodium, ruthenium, tungsten, and molybdenum. By changing the amounts of these metals, they created four different alloys, each with a different crystal structure, and investigated their mechanical behavior at room temperature and 1500 °C.

 

"These alloys showed a clear difference in strength at room temperature depending on the crystal structure. However, at 1500°C, these differences disappeared." Matsunaga explained. " This means that different deformation mechanisms are active at room temperature and 1500°C and that temperature has a greater impact on deformation mechanisms than crystal structure at elevated temperatures."

This study reveals that the mechanical properties of  RCCAs are more influenced by temperature than by their crystal structure. Understanding how these alloys deform under different temperatures is crucial for designing new materials that can withstand high temperatures. This research could lead to the development of next-generation materials that perform reliably in extreme conditions far beyond the capabilities of traditional metals and alloys.

The team's findings has been published in the peer-reviewed journal, Materials Science and Engineering A. Their research has received funding from the TANAKA Memorial Foundation.

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Publication: Materials Science & Engineering A

Title: The effect of constituent phases on microstructure and high temperature deformation mechanisms of IrRhRuWMo complex concentrated alloys

Authors: S. Matsunaga*, O. Shimizu, S. Liang, Y.-N. Shen, Y. Yamabe-Mitarai

DOI: 10.1016/j.msea.2024.147018

URL: https://doi.org/10.1016/j.msea.2024.147018