Ultrahigh high-strain-rate superplasticity in a nanostructured high-entropy alloy

Nature Communications

Peyman Asghari-Rad¹  Nhung Thi-Cam Nguyen¹  Praveen Sathiyamoorthi¹  Hyoung Seop Kim²  Chong Soo Lee³  Alireza Zargaran³ 

[1]Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 37673, Pohang, South Korea

[2]Center for High Entropy Alloys, Pohang University of Science and Technology (POSTECH), 37673, Pohang, South Korea

[3]Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 37673, Pohang, South Korea

[4]Center for High Entropy Alloys, Pohang University of Science and Technology (POSTECH), 37673, Pohang, South Korea

[5]Graduate Institute of Ferrous Technology, Pohang University of Science and Technology (POSTECH), 37673, Pohang, South Korea

[6]Graduate Institute of Ferrous Technology, Pohang University of Science and Technology (POSTECH), 37673, Pohang, South Korea

DOI  :  10.1038/s41467-020-16601-1

来源: Springer

【 摘 要 】

Superplasticity describes a material’s ability to sustain large plastic deformation in the form of a tensile elongation to over 400% of its original length, but is generally observed only at a low strain rate (~10−4 s−1), which results in long processing times that are economically undesirable for mass production. Superplasticity at high strain rates in excess of 10−2 s−1, required for viable industry-scale application, has usually only been achieved in low-strength aluminium and magnesium alloys. Here, we present a superplastic elongation to 2000% of the original length at a high strain rate of 5 × 10−2 s−1 in an Al9(CoCrFeMnNi)91 (at%) high-entropy alloy nanostructured using high-pressure torsion. The high-pressure torsion induced grain refinement in the multi-phase alloy combined with limited grain growth during hot plastic deformation enables high strain rate superplasticity through grain boundary sliding accommodated by dislocation activity.

【 授权许可】

CC BY