Microstructural and mechanical behavior of a CoCrFeNiCu4 non-equiatomic high entropy alloy
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2021年第1期
论文作者：Zijuan Xu Zhongtao Li Yang Tong Weidong Zhang Zhenggang Wu
文章页码：35 - 43
摘 要：High entropy alloy（HEA）-based alloy design is experiencing a conceptual broadening from equiatomic alloys to non-equiatomic alloys.To provide experimental basis for designing Cu-rich non-equiatomic HEAs,in the current study,a dual phase（Cu-rich and CoCrFeNi-rich phases） face-centered cubic CoCrFeNiCu4 alloy was systematically investigated.We provided initial and experiment-based understanding of the behavioral change of the alloy during a variety of thermal cycles and thermomechanical processing.The current results indicate that,during heating,preferred precipitation of Cu-rich particles occurs,leading to more pronounced compositional differences between the two constituent FCC phases and increased relative volume fraction of the Cu-rich phase.The Alloy exhibits a continuous melting and discontinuous solidification of the Cu-rich and CoCrFeNi-rich phases.After being cold-rolled to ～90 % thickness reduction,the alloy exhibits a recrystallization temperature higher than 800℃.Annealing at 300 and 500℃ led to strength reduction and/or ductility decrease;further increasing annealing temperature monotonically caused softening and ductilization due to decreased density of pre-existing dislocations.The yield-drop phenomena observed for the 900℃-and 1000℃-annealed specimens are associated with the locking of pre-existing dislocations by some "atmosphere",the nature of which warrants further elucidation.
Zijuan Xu1，Zhongtao Li1，Yang Tong2，Weidong Zhang1，Zhenggang Wu1,3
1. College of Materials Science and Engineering, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Hunan University2. Materials Science and Technology Division, Oak Ridge National Laboratory3. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University
摘 要：High entropy alloy（HEA）-based alloy design is experiencing a conceptual broadening from equiatomic alloys to non-equiatomic alloys.To provide experimental basis for designing Cu-rich non-equiatomic HEAs,in the current study,a dual phase（Cu-rich and CoCrFeNi-rich phases） face-centered cubic CoCrFeNiCu4 alloy was systematically investigated.We provided initial and experiment-based understanding of the behavioral change of the alloy during a variety of thermal cycles and thermomechanical processing.The current results indicate that,during heating,preferred precipitation of Cu-rich particles occurs,leading to more pronounced compositional differences between the two constituent FCC phases and increased relative volume fraction of the Cu-rich phase.The Alloy exhibits a continuous melting and discontinuous solidification of the Cu-rich and CoCrFeNi-rich phases.After being cold-rolled to ～90 % thickness reduction,the alloy exhibits a recrystallization temperature higher than 800℃.Annealing at 300 and 500℃ led to strength reduction and/or ductility decrease;further increasing annealing temperature monotonically caused softening and ductilization due to decreased density of pre-existing dislocations.The yield-drop phenomena observed for the 900℃-and 1000℃-annealed specimens are associated with the locking of pre-existing dislocations by some "atmosphere",the nature of which warrants further elucidation.
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