Deformation mechanisms of Al0.1CoCrFeNi at elevated temperatures

作者：Yang Tengfei^*; Tang Zhi; Xie Xie; Carroll Robert; Wang Gongyao; Wang Yugang; Dahmen Karin A; Liaw Peter K; Zhang Yanwen

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2017, 684: 552-558.

DOI：10.1016/jansea.2016.12.110

• High-entropy alloy
• Transmission electron microscopy
• Mechanical properties
• Microstructure

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.

• 出版日期2017-1-27
• 单位北京大学