A molecular dynamics study on mechanical performance and deformation mechanisms in nanotwinned NiCo-based alloys with nano-precipitates under high temperatures  

作　　者：Zihao Yu Hongyu Wang Ligang Sun Zhihui Li Linli Zhu 于子皓;王鸿宇;孙李刚;李志辉;朱林利(School of Aeronautics and Astronautics,Center for X-Mechanics,Zhejiang University,Hangzhou 310027,China;School of Science,Harbin Institute of Technology,Shenzhen 518067,China;Hypervelocity Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China;National Laboratory for Computational Fluid Dynamics,Beijing 100191,China)

机构地区：[1]School of Aeronautics and Astronautics,Center for X-Mechanics,Zhejiang University,Hangzhou 310027,China [2]School of Science,Harbin Institute of Technology,Shenzhen 518067,China [3]Hypervelocity Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China [4]National Laboratory for Computational Fluid Dynamics,Beijing 100191,China

出　　处：《Chinese Physics B》2024年第11期349-355,共7页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.12072317);the Natural Science Foundation of Zhejiang Province(Grant No.LZ21A020002);Ligang Sun gratefully acknowledges the support received from the Guangdong Basic and Applied Basic Research Foundation(Grant No.22022A1515011402);the Science,Technology and Innovation Commission of Shenzhen Municipality(Grant No.GXWD20231130102735001);Development and Reform Commission of Shenzhen(Grant No.XMHT20220103004).

摘　　要：Molecular dynamics simulations are performed to investigate the mechanical behavior of nanotwinned NiCo-based alloys containing coherent L1_(2) nano-precipitates at different temperatures,as well as the interactions between the dislocations and nano-precipitates within the nanotwins.The simulation results demonstrate that both the yield stress and flow stress in the nanotwinned NiCo-based alloys with nano-precipitates decrease as the temperature rises,because the higher temperatures lead to the generation of more defects during yielding and lower dislocation density during plastic deformation.Moreover,the coherent L1_(2) phase exhibits excellent thermal stability,which enables the hinderance of dislocation motion at elevated temperatures via the wrapping and cutting mechanisms of dislocations.The synergistic effect of nanotwins and nano-precipitates results in more significant strengthening behavior in the nanotwinned NiCo-based alloys under high temperatures.In addition,the high-temperature mechanical behavior of nanotwinned NiCo-based alloys with nano-precipitates is sensitive to the size and volume fraction of the microstructures.These findings could be helpful for the design of nanotwins and nano-precipitates to improve the high-temperature mechanical properties of NiCo-based alloys.

关 键 词：NiCo-based alloys high temperature nano-precipitate NANOTWINS molecular dynamics simulation mechanical behavior deformation mechanism dislocations 

分 类 号：TG146.15[一般工业技术—材料科学与工程] TB383.1[金属学及工艺—金属材料]