MnFeCoCuNix high-entropy alloys(HEAs)with different Ni contents were fabricated by vacuum induction melting.XRD and SEM−EDS were used to analyze the phase constitution and structure,and the tensile properties of the s...MnFeCoCuNix high-entropy alloys(HEAs)with different Ni contents were fabricated by vacuum induction melting.XRD and SEM−EDS were used to analyze the phase constitution and structure,and the tensile properties of the samples were determined using a universal tensile tester.The results show that the HEAs consist of a dual-phase structure,in which FCC1 phase is rich in Fe and Co,while the FCC2 phase has high contents of Cu and Mn.As Ni content increases,the segregation of Cu decreases,accompanied by the decrease of FCC2 phase.Moreover,the tensile strength of the HEAs increases first and then decreases,and the elongation increases slightly.This is attributed to the combined effect of interface strengthening and solid solution strengthening.The in-situ stretched MnFeCoCuNi0.5 alloy shows obvious neck shrinkage during the tensile fracture process.In the initial deformation stage,the slip lines show different morphologies in the dual-phase structure.However,in the later stage,the surface slip lines become longer and denser due to the redistribution of atoms and the re-separation of the dissolved phase.展开更多
V_(x)FeCoNiCu high entropy alloy matrix composites reinforced by in situ TiC particles(10 vol.%),i.e.,V_(x)FeCoNiCu/TiC composites,were fabricated from V–Fe–Co–Ni–Cu–Ti–C system using vacuum inductive melting me...V_(x)FeCoNiCu high entropy alloy matrix composites reinforced by in situ TiC particles(10 vol.%),i.e.,V_(x)FeCoNiCu/TiC composites,were fabricated from V–Fe–Co–Ni–Cu–Ti–C system using vacuum inductive melting method.With the content of vanadium increasing,the size of TiC particles decreased gradually.Meanwhile,vanadium agglomeration occurred slightly.The reaction mechanism of the mixed powder(Fe,V,Ti and C)and the mechanical properties of obtaining V_(x)FeCoNiCu/TiC composites were studied.It was found that three reactions occurred(Fe-Ti-FeTi-Fe_(2)Ti,FeTi-Fe_(2)Ti-Fe-Ti and Ti-C-TiC)in the heating process.The apparent activation energy for these three reactions was calculated and found to be 26.4,698.3 and 1879.0 kJ/mol,respectively.At room temperature,tensile strength and elongation increased first and then decreased with the increase in vanadium content and the microhardness increased gradually.The maximum tensile strength of the composites was determined to be 666 MPa,representing a 17.7%increase over that of FeCoNiCu/TiC high entropy alloy composites.展开更多
基金The authors are grateful for the financial supports from the Jiangsu Provincial Science and Technology Plan Project,China(BE2018753/KJ185629)the National Natural Science Foundation of China(51571118)the 2020 Extracurricular Academic Research Fund for College Students of Nanjing University of Science and Technology,China.Zong-han XIE acknowledges the support of the Australian Research Council Discovery Projects.
文摘MnFeCoCuNix high-entropy alloys(HEAs)with different Ni contents were fabricated by vacuum induction melting.XRD and SEM−EDS were used to analyze the phase constitution and structure,and the tensile properties of the samples were determined using a universal tensile tester.The results show that the HEAs consist of a dual-phase structure,in which FCC1 phase is rich in Fe and Co,while the FCC2 phase has high contents of Cu and Mn.As Ni content increases,the segregation of Cu decreases,accompanied by the decrease of FCC2 phase.Moreover,the tensile strength of the HEAs increases first and then decreases,and the elongation increases slightly.This is attributed to the combined effect of interface strengthening and solid solution strengthening.The in-situ stretched MnFeCoCuNi0.5 alloy shows obvious neck shrinkage during the tensile fracture process.In the initial deformation stage,the slip lines show different morphologies in the dual-phase structure.However,in the later stage,the surface slip lines become longer and denser due to the redistribution of atoms and the re-separation of the dissolved phase.
基金the Jiangsu Province Science and Technology Plan Project(No.BE2018753/KJ185629)the National Natural Science Foundation of China(Nos.51571118 and 51371098).
文摘V_(x)FeCoNiCu high entropy alloy matrix composites reinforced by in situ TiC particles(10 vol.%),i.e.,V_(x)FeCoNiCu/TiC composites,were fabricated from V–Fe–Co–Ni–Cu–Ti–C system using vacuum inductive melting method.With the content of vanadium increasing,the size of TiC particles decreased gradually.Meanwhile,vanadium agglomeration occurred slightly.The reaction mechanism of the mixed powder(Fe,V,Ti and C)and the mechanical properties of obtaining V_(x)FeCoNiCu/TiC composites were studied.It was found that three reactions occurred(Fe-Ti-FeTi-Fe_(2)Ti,FeTi-Fe_(2)Ti-Fe-Ti and Ti-C-TiC)in the heating process.The apparent activation energy for these three reactions was calculated and found to be 26.4,698.3 and 1879.0 kJ/mol,respectively.At room temperature,tensile strength and elongation increased first and then decreased with the increase in vanadium content and the microhardness increased gradually.The maximum tensile strength of the composites was determined to be 666 MPa,representing a 17.7%increase over that of FeCoNiCu/TiC high entropy alloy composites.
