Flow stress softening and deformation mechanism under competition of current density and strain rate in basket structured high-entropy alloy

IF 9.6 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Rare Metals Pub Date : 2025-01-20 DOI:10.1007/s12598-024-03099-5

Hu-Shan Li, Chao-Gang Ding, Hao Zhang, Jing-Yi Wang, Yu-Xi Chen, Zhi-Qin Yang, Jie Xu, Bin Guo, De-Bin Shan, Terence G. Langdon

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引用次数: 0

Abstract

Electrically assisted forming (EAF) is a reliable method of reducing the deformation resistance of metallic materials and enhancing their formability. In this study, the mechanical properties and microstructure of Al_0.5CoCrFeNi high-entropy alloy (HEA) under electrically assisted compression (EAC) were investigated. The results showed that the flow stress decreased with increasing current density in the EAC. Specifically, the flow curves exhibited S-shaped softening at a higher current density, which was dominated by the non-uniform distribution of the Joule heating temperature during EAC. When the flow stress was fixed at 500 MPa and 80 A·mm⁻², compressible deformation amounts of 63.7% were observed at a strain rate of 1 s⁻¹, indicating full compression of Al_0.5CoCrFeNi HEA at low-stress levels. Based on the microstructure, the flowability of Al_0.5CoCrFeNi HEA was improved during EAC, and the flow direction shifted from 45°to the horizontal direction. The current density, which influences the Joule heating temperature and strain rate, synergistically affects the stacking fault energy (SFE) and critical resolved shear stress (CRSS), which affect the tendency for twinning behavior. Thererfore, deformation nanoscale twins (DTs) were observed, indicating a shift in the deformation mechanisms from dislocation slip domination to a mixed pattern of dislocation slip and twinning. This study confirmed the deformability of Al_0.5CoCrFeNi HEA during EAC and provided an experimental foundation and theoretical support for the formation of HEAs.

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来源期刊

Rare Metals 工程技术-材料科学：综合

CiteScore

12.10

自引率

12.50%

发文量

2919

审稿时长

2.7 months

期刊介绍： Rare Metals is a monthly peer-reviewed journal published by the Nonferrous Metals Society of China. It serves as a platform for engineers and scientists to communicate and disseminate original research articles in the field of rare metals. The journal focuses on a wide range of topics including metallurgy, processing, and determination of rare metals. Additionally, it showcases the application of rare metals in advanced materials such as superconductors, semiconductors, composites, and ceramics.