Research ArticleMATERIALS SCIENCE

Grain boundary decohesion by nanoclustering Ni and Cr separately in CrMnFeCoNi high-entropy alloys

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Science Advances  06 Dec 2019:
Vol. 5, no. 12, eaay0639
DOI: 10.1126/sciadv.aay0639

Abstract

The loss of ductility with temperature has been widely observed in tensile tests of single-phase face-centered cubic structured high-entropy alloys (HEAs). However, the fundamental mechanism for such a ductility loss remains unknown. Here, we show that ductility loss in the CrMnFeCoNi HEA upon deformation at intermediate temperatures is correlated with cracking at grain boundaries (GBs). Nanoclustering Cr, Ni, and Mn separately at GBs, as detected by atom probe tomography, reduces GB cohesion and promotes crack initiation along GBs. We further demonstrated a GB segregation engineering strategy to avoid ductility loss by shifting the fast segregation of principal elements from GBs into preexisting Cr-rich secondary phases. We believe that GB decohesion by nanoclustering multiprincipal elements is a common phenomenon in HEAs. This study not only provides insights into understanding ductility loss but also offers a strategy for tailoring ductility-temperature relations in HEAs.

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

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