We applied an approach to the development of many-body interatomic potentials for NiZr alloys,gaining an improved accuracy and reliability.The functional form of the potential is that of the embedded method,but it has...We applied an approach to the development of many-body interatomic potentials for NiZr alloys,gaining an improved accuracy and reliability.The functional form of the potential is that of the embedded method,but it has been improved as follows. (1) The database used for the development of the potential includes both experimental data and a large set of energies of different structures of the alloys generated by Fab initio calculations. (2) The optimum parametrization of the potential for the given database is obtained by fitting. Using this approach we developed reliable interatomic potentials for Ni and Zr. The potential accurately reproduces basic equilibrium properties of the alloys.展开更多
Single-phase NiZr2 intermetallic compound nanocrystalline samples were synthesized by fully crystallizing the parent amorphous NiZr2 alloy at the temperature interval of 653~1073 K for a certain period of time. High r...Single-phase NiZr2 intermetallic compound nanocrystalline samples were synthesized by fully crystallizing the parent amorphous NiZr2 alloy at the temperature interval of 653~1073 K for a certain period of time. High resolution electron microscope (HREM) observations on the nanophase NiZr2 reveal a Iamellar nano-tWin structure with (110) direction on the nanometer scale, being typically a few interatomic distances to a few nanometers. Microhardness measurements on the single-phase NiZr2 samples indicate that the hardness of nanotwinned NiZr2 is obviously increased in comparison to the amorphous counterpart. When the average grain size increases from 19.1 to 93.9 nm, the variation of the hardness with the average grain size obeys the normal Hall-Petch relation, whereas as the average grain size is smaller than 19.1 nm. the microhardness data deviate from the above relation.展开更多
Formation of icosahedral dusters in rapidly solidified binary amorphous NixZr100-x （x = 15, 33.3, 50, 66.7, 85） is studied by using molecular dynamics simulation methods. A large number of icosahedral dusters with 1...Formation of icosahedral dusters in rapidly solidified binary amorphous NixZr100-x （x = 15, 33.3, 50, 66.7, 85） is studied by using molecular dynamics simulation methods. A large number of icosahedral dusters with 13 atoms （Ih13） were observed in NixZr100-x alloys, and most of them, even those in Zr-rich alloys, are found to be Ni-centred. Studies on the structures of Ni33.3Z66.7 obtained at different cooling rates demonstrate that most of iscosahedral dusters enhanced by decreasing cooling rates are also Ni-centred, The essentials of Ni atoms preferring to be the core of icosahedral clusters are illustrated with the criterion of energy minimization and the equilibrium interatomic distances between different atoms.展开更多
基金Supported by the National Natural Science Foundation of China(No.2 9892 16 6 ,2 980 30 0 6 ,2 99830 0 1)
文摘We applied an approach to the development of many-body interatomic potentials for NiZr alloys,gaining an improved accuracy and reliability.The functional form of the potential is that of the embedded method,but it has been improved as follows. (1) The database used for the development of the potential includes both experimental data and a large set of energies of different structures of the alloys generated by Fab initio calculations. (2) The optimum parametrization of the potential for the given database is obtained by fitting. Using this approach we developed reliable interatomic potentials for Ni and Zr. The potential accurately reproduces basic equilibrium properties of the alloys.
文摘Single-phase NiZr2 intermetallic compound nanocrystalline samples were synthesized by fully crystallizing the parent amorphous NiZr2 alloy at the temperature interval of 653~1073 K for a certain period of time. High resolution electron microscope (HREM) observations on the nanophase NiZr2 reveal a Iamellar nano-tWin structure with (110) direction on the nanometer scale, being typically a few interatomic distances to a few nanometers. Microhardness measurements on the single-phase NiZr2 samples indicate that the hardness of nanotwinned NiZr2 is obviously increased in comparison to the amorphous counterpart. When the average grain size increases from 19.1 to 93.9 nm, the variation of the hardness with the average grain size obeys the normal Hall-Petch relation, whereas as the average grain size is smaller than 19.1 nm. the microhardness data deviate from the above relation.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50225103 and 50471001.
文摘Formation of icosahedral dusters in rapidly solidified binary amorphous NixZr100-x （x = 15, 33.3, 50, 66.7, 85） is studied by using molecular dynamics simulation methods. A large number of icosahedral dusters with 13 atoms （Ih13） were observed in NixZr100-x alloys, and most of them, even those in Zr-rich alloys, are found to be Ni-centred. Studies on the structures of Ni33.3Z66.7 obtained at different cooling rates demonstrate that most of iscosahedral dusters enhanced by decreasing cooling rates are also Ni-centred, The essentials of Ni atoms preferring to be the core of icosahedral clusters are illustrated with the criterion of energy minimization and the equilibrium interatomic distances between different atoms.
