2013 journal article

Significant hardening due to the formation of a sigma phase matrix in a high entropy alloy

INTERMETALLICS, 33, 81–86.

By: M. Tsai n, H. Yuan n, G. Cheng n, W. Xu n, W. Jian n, M. Chuang*, C. Juan*, A. Yeh*, S. Lin*, Y. Zhu n

co-author countries: Taiwan, Province of China 🇹🇼 United States of America 🇺🇸
author keywords: Age-hardening; Precipitates; Electron microscopy, transmission
Source: Web Of Science
Added: August 6, 2018

The hardening in Al0.3CrFe1.5MnNi0.5 high-entropy alloy not only nearly triples the hardness of the alloy, but also shows a quick hardening response and the absence of overaging. However, the crystal structure, morphology, and composition of the hardening phase have not yet been confirmed. Here, such information regarding the hardening phase is investigated. It was found that the hardening phase is a Cr–Mn–Fe ternary sigma phase. Unlike in conventional engineering alloys, the sigma phase is not precipitated from the matrix, instead, the whole BCC matrix transforms to sigma phase almost without changing its composition. Therefore, the hardening phenomenon is not a precipitation hardening reaction as suggested before.