Nb has a positive effect on improving the mechanical properties of metal materials, and it is expected to strengthen CoCrCuFeNi high-entropy alloys （HEAs） with outstanding ductility and relatively weak strength. In ...Nb has a positive effect on improving the mechanical properties of metal materials, and it is expected to strengthen CoCrCuFeNi high-entropy alloys （HEAs） with outstanding ductility and relatively weak strength. In this paper, the alloying effects of Nb on the microstructural evolution and the mechanical properties of the （CoCrCuFeNi）100-xNbx HEA were investigated systematically. The result shows that Nb promotes the phase transition from FCC （face-centered cubic） to Laves phase, and the volume fractions of Laves phase increase from 0% to 58.2% as the Nb content increases, Compressive testing shows that the addition of Nb has a positive effect on improving the strength of CoCrCuFeNi HEA. The compressive yield strength of （CoCrCuFeNi）100-xNbx HEAs increases from 338 MPa to 1322 MPa and the fracture strain gradually reduces from 60.0% （no fracture） to 8.1% as the Nb content increases from 0 to 16 at.%. The volume fraction increase of hard Laves phase is the key factor for the strength increase, and the reduction of the VEC （valence electron concentration） value induced by the addition of Nb is beneficial for the increase of the Laves phase content in these alloys.展开更多
In order to strengthen the face-centered-cubic(FCC) type CoCrFeMnNi high entropy alloys(HEAs), different contents of Mo(0–16 at.%, similarly hereinafter) were alloyed. Phase evolution, microstructure,mechanical prope...In order to strengthen the face-centered-cubic(FCC) type CoCrFeMnNi high entropy alloys(HEAs), different contents of Mo(0–16 at.%, similarly hereinafter) were alloyed. Phase evolution, microstructure,mechanical properties and related mechanism of these HEAs were systematically studied. The results show that sigma phase is appeared with addition of Mo, and the volume fraction of it increases gradually from 0 to 66% with increasing Mo content. It is found that Mo is enriched in sigma phase, which indicates that Mo element is beneficial to form sigma phase. Compressive testing shows that the yield strength of the alloys increases gradually from 216 to 765 MPa, while the fracture strain decreases from 50%(no fracture) to 19% with increasing of Mo. The alloy exhibits the best compressive performance when Mo content reaches 11%, the yield strength, fracture strength and fracture strain are 547 MPa, 2672 MPa and44% respectively. The increased volume fraction of sigma phase plays an important role in improving the compressive strength of(CoCrFeMnNi)_(100-x)Mo_xHEAs.展开更多
基金supported by the National Natural Science Foundation of China (No. 51331005)the National Science Fund for Distinguished Young Scholars (No. 51425402)
文摘Nb has a positive effect on improving the mechanical properties of metal materials, and it is expected to strengthen CoCrCuFeNi high-entropy alloys （HEAs） with outstanding ductility and relatively weak strength. In this paper, the alloying effects of Nb on the microstructural evolution and the mechanical properties of the （CoCrCuFeNi）100-xNbx HEA were investigated systematically. The result shows that Nb promotes the phase transition from FCC （face-centered cubic） to Laves phase, and the volume fractions of Laves phase increase from 0% to 58.2% as the Nb content increases, Compressive testing shows that the addition of Nb has a positive effect on improving the strength of CoCrCuFeNi HEA. The compressive yield strength of （CoCrCuFeNi）100-xNbx HEAs increases from 338 MPa to 1322 MPa and the fracture strain gradually reduces from 60.0% （no fracture） to 8.1% as the Nb content increases from 0 to 16 at.%. The volume fraction increase of hard Laves phase is the key factor for the strength increase, and the reduction of the VEC （valence electron concentration） value induced by the addition of Nb is beneficial for the increase of the Laves phase content in these alloys.
基金Science and Technology Advancement Project in Jiangsu Province(BE2018753/KJ185629)National Natural Science Foundation of China(51571118,51371098)2020 Extracurricular Academic Research Fund for College Students of Nanjing University of Science and Technology。
基金supported by the Fund of State Key Laboratory of Advanced Welding and Joining,and the National Natural Science Foundation of China (No.51741404)
文摘In order to strengthen the face-centered-cubic(FCC) type CoCrFeMnNi high entropy alloys(HEAs), different contents of Mo(0–16 at.%, similarly hereinafter) were alloyed. Phase evolution, microstructure,mechanical properties and related mechanism of these HEAs were systematically studied. The results show that sigma phase is appeared with addition of Mo, and the volume fraction of it increases gradually from 0 to 66% with increasing Mo content. It is found that Mo is enriched in sigma phase, which indicates that Mo element is beneficial to form sigma phase. Compressive testing shows that the yield strength of the alloys increases gradually from 216 to 765 MPa, while the fracture strain decreases from 50%(no fracture) to 19% with increasing of Mo. The alloy exhibits the best compressive performance when Mo content reaches 11%, the yield strength, fracture strength and fracture strain are 547 MPa, 2672 MPa and44% respectively. The increased volume fraction of sigma phase plays an important role in improving the compressive strength of(CoCrFeMnNi)_(100-x)Mo_xHEAs.
