Strong grain-size effect on deformation twinning of an Al_0.1CoCrFeNi high-entropy alloy

ABSTRACT

An Al_0.1CoCrFeNi high-entropy alloy (HEA) with a face-centered cubic structure in the as-cast and the recrystallized states is investigated. The mean grain size of the as-cast HEA is 14 times larger than that of the recrystallized HEA. The tension tests reveal that deformation twinning is the main mechanism dominating the plastic deformation of two HEAs. With a decrease in the grain size, twin spacing increases, and twin thickness decreases, which results in a low twinning activity. The twinning activity of the recrystallized HEA is strongly inhibited by grain refinement, which degrades the promotion of twinning on the strain-hardening ability and the tensile ductility.

GRAPHICAL ABSTRACT

IMPACT STATEMENT

Grain refinement on strain hardening and twinning in a high-entropy alloy (HEA) is investigated, which is associated with the nanotwin substructure. Grain refinement decreases the twin thickness, and increases the twin spacing.

KEYWORDS:

• High-entropy alloys
• mechanical properties
• deformation twinning
• strain hardening
• grain refinement

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the National Key Basic Research Program from MOST (No. 2015CB856800), and the NSFC (Nos. 51671120 and 51501106). PKL would like to acknowledge the Department of Energy (DOE), Office of Fossil Energy, National Energy Technology Laboratory (DE-FE-0008855 and DE-FE-0024054, and DE-FE-0011194), with Mr V. Cedro and M. R. Dunst as program managers. PKL thank the support from the project of DE-FE-0011194 with the program manager, Dr J. Mullen. PKL very much appreciate the support of the U.S. Army Research Office project (W911NF-13-1-0438) with the program manager, Dr D. M. Stepp. PKL thanks the support from the National Science Foundation (CMMI-1100080 and DMR-1611180) with the program directors, Dr C. Cooper and D. Farkas.