摘要
采用冷轧和退火热处理工艺制备了不完全再结晶结构的Fe_(40)Mn_(10)Cr_(25)Ni_(25)高熵合金,分析了合金的室温(298 K)及低温(77 K)拉伸时的力学性能。结果表明,合金具有优良的室温及低温力学性能,合金在低温拉伸时强度和塑性均得到了提高,其室温强度和断后伸长率分别为880 MPa和18%,低温强度和断后伸长率分别为1360 MPa和36%。合金在室温变形以位错滑移为主,低温变形以位错滑移和孪生为主。室温拉伸时,粗晶晶粒先于细晶晶粒变形,导致试样内部产生了应变梯度,提高了合金的加工硬化率,使合金在室温下具有良好的强塑性。低温拉伸时,粗晶晶粒中形成了大量的变形孪晶,从而提高了合金的低温力学性能。
The Fe_(40)Mn_(10)Cr_(25)Ni_(25) high-entropy alloy(HEA)with partial recrystallization was prepared by cold rolling and subsequent annealing.The tensile properties of the alloy at room temperature(298 K)and cryogenic temperature(77 K)were studied.The results show that the alloy has excellent room temperature and cryogenic temperature mechanical properties.Both the strength and ductility of the alloy are improved under tension at cryogenic temperature.The strength and percentage elongation after fracture at room temperature are 880 MPa and 18% respectively,and 1360 MPa and 36% respectively at 77 K.The tensile deformation of the alloy at room temperature is dominated by dislocation slip,but by dislocation slip and twinning at cryogenic temperature.The coarse grains deform before fine grains under tensile stress at room temperature,resulting in a strain gradient inside the specimen,so that the work hardening rate of the alloy is increased,the alloy exhibits excellent combination of strength and ductility at room temperature.A large quantity of high-density deformation twins are formed in the coarse grains under tensile stress at cryogenic temperature,so that the cryogenic temperature mechanical properties of the alloy can be improved.
作者
武雅桃
黄德军
杨慧君
张敏
乔珺威
Wu Yatao;Huang Dejun;Yang Huijun;Zhang Min;Qiao Junwei(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan Shanxi 030024,China;Malvern Panalytical(China)Co.,Ltd.,Shanghai 201100,China;Key Laboratory of Interface Science and Engineering in Advanced Materials,Ministry of Education,Taiyuan University of Technology,Taiyuan Shanxi 030024,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2021年第6期160-167,共8页
Heat Treatment of Metals
基金
山西省自然科学基金(201901D111105,201901D111114)
新金属材料国家重点实验室开放课题(2020-Z09)。
关键词
高熵合金
显微组织
力学性能
位错
孪晶
high-entropy alloy
microstructure
mechanical properties
dislocation
twin
