Deformation mechanisms of Al0.1CoCrFeNi at elevated temperatures

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:684

Article

Yang, Tengfei^1,2  Tang, Zhi¹  Xie, Xie¹  Carroll, Robert⁴  Wang, Gongyao¹  Wang, Yugang²  Dahmen, Karin A.⁴  Liaw, Peter K.¹  Zhang, Yanwen^1,3 

[1] Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA

[2] Peking Univ, Ctr Appl Phys & Technol, State Key Lab Nucl Phys & Technol, Beijing 100871, Peoples R China

[3] Oak Ridge Natl Lab, Mat Sci & Technol Div, Oak Ridge, TN 37831 USA

[4] Univ Illinois, Dept Phys, 1110 West Green St, Urbana, IL 61801 USA

关键词: High-entropy alloy;    Transmission electron microscopy;    Mechanical properties;    Microstructure;   

DOI  :  10.1016/j.msea.2016.12.110

来源: Elsevier

【 摘 要 】

Deformation mechanisms of a high-entropy alloy with a single face-centered-cubic phase, Al0.3CoCrFeNi, at elevated temperatures are studied to explore the high temperature performances of high-entropy alloys. Tensile tests at a strain rate of 10(-4) s(-1) are performed at different temperatures ranging from 25 to 700 degrees C. While both yield strength and ultimate tensile strength decrease with increasing temperature, the maximum elongation to fracture occurred at 500 degrees C. Transmission electron microscopy characterizations reveal that, at both 25 and 500 degrees C, most of deformation occurs by dislocation glide on the normal face-centered-cubic slip system, {111} (110). In contrast, numerous stacking faults are observed at 600 and 700 degrees C, accompanied by the decreasing of dislocation density, which are attributed to the motion of Shockley partials and the dissociation of dislocations, respectively. According to the Considere's criterion, it is assumed that the dissociation of dislocations and movement of Shockley partials at higher temperatures significantly decreases the work hardening during tensile tests, promoting the early onset of necking instability and decreasing the high-temperature ductility.

【 授权许可】

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