Title

Adaptive attenuation of hierarchical composition fluctuations augments the plastic strain of a high entropy steel

Document Type

Journal Article

Publication Title

Materials Science and Engineering A

Volume

857

Publisher

Elsevier

School

School of Engineering

Funders

Australian Research Council / Australian Government Research Training Program Scholarship

Grant Number

ARC Numbers : DP200103152, DE210101773

Grant Link

http://purl.org/au-research/grants/arc/DP200103152 http://purl.org/au-research/grants/arc/DE210101773

Comments

Tsianikas, S., Chen, Y., Slattery, A., Peters, J., & Xie, Z. (2022). Adaptive attenuation of hierarchical composition fluctuations augments the plastic strain of a high entropy steel. Materials Science and Engineering: A, 857, Article 144037. https://doi.org/10.1016/j.msea.2022.144037

Abstract

A body-centred cubic (BCC) high entropy steel with a spinodal-like nanopattern and atomic-scale local chemical fluctuations exhibits controlled attenuation of its chemical complexity with deformation. Changes in the chemical composition of the spinodal structure measured using energy dispersive X-ray spectroscopy reveal that the average composition peak-to-peak amplitude decreases by 67 % from 4.9 at.% to 1.6 at.% with increasing strain. On the other hand, the short-range chemical fluctuations, assessed with atomic strain mapping, displays a 48 % decrease in the average strain peak-to-peak amplitude from 3.03 at.% to 1.59 at.% under mechanical loading. The reduction in local strain brought about by increased chemical homogeneity at both levels enables more uniform, steady deformation leading to extended ductility (13.7±1.9 %), all the while maintaining ultrahigh strength (2.92 ± 0.36 GPa, placing it among the highest values reported). The interactions between dislocations and concentration waves are identified and found to be responsible for this compelling effect on the newly created steel.

DOI

10.1016/j.msea.2022.144037

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