Within the framework of the embedded-atom method, we performed molecular-dynamics calculations to investigate the structural transformation during melting of two copper clus- ters containing 57 and 58 atoms. The simul...Within the framework of the embedded-atom method, we performed molecular-dynamics calculations to investigate the structural transformation during melting of two copper clus- ters containing 57 and 58 atoms. The simulation results reveal how their different structural changes can strongly influence internal energy and radial distribution functions. The local structural patterns of different regions during the temperature increase, determined by atom density profiles, are identified for the melting of each cluster. The simulations show sensi- tivities of the structural changes for these two small size clusters with different structures.展开更多
With the Voter-Chen version of embedded-atom model （EAM） potential and molecular dynamics, the melting of Ni3Al alloy was simulated by one-phase （conventional） and two-phase approaches. It is shown that the simula...With the Voter-Chen version of embedded-atom model （EAM） potential and molecular dynamics, the melting of Ni3Al alloy was simulated by one-phase （conventional） and two-phase approaches. It is shown that the simulated melting point is dependent on the potential and the simulation method. The structures of the melts obtained by different simulation methods were analyzed by the pair correlation function, the coordination number, and the distribution of atom pair type （indexed by the Honeycutt-Andersen pair analysis technique）. The results show that the structures are very similar.展开更多
We report on molecular dynamics simulations performed using microcanonical ensemble to predict the melting of argon particles in nanometer size range 10 nm and to investigate the effect of the time step integration. W...We report on molecular dynamics simulations performed using microcanonical ensemble to predict the melting of argon particles in nanometer size range 10 nm and to investigate the effect of the time step integration. We use the Lennard- Jones potential functions to describe the interatomic interactions, and the results are evaluated by using caloric curves of the melting phenomenon. Thermodynamic properties, including the total energy, Lindemann parameter, kinetic and potential distribution’s functions, are used to characterize the melting process. The data shows bimodal behavior only in a certain interval of integration time step Δt, while the internal energy increases monotonically with the temperature. For the other time step values, the back bending disappears. We claim that negative specific heat is related to a possible decrease of entropy in an isolated system;this can be interpreted as a result of the internal interactions, especially attractive process and specific relaxation time.展开更多
Based on the quantum Sutton-Chen many-body potential,a molecular dynamics simulation was performed to investigate the formation and evolution properties of clusters in liquid Cu with 50 000 atoms.The cluster-type inde...Based on the quantum Sutton-Chen many-body potential,a molecular dynamics simulation was performed to investigate the formation and evolution properties of clusters in liquid Cu with 50 000 atoms.The cluster-type index method(CTIM)was used to describe the complex microstructure transitions.It is demonstrated that the amorphous structures are mainly formed with the three bond-types of 1551,1541 and 1431 in the system,and the icosahedral cluster(12 0 12 0)and other basic polyhedron clusters of(12 2 8 2),(13 1 10 2),(13 3 6 4),(14 1 10 3),(14 2 8 4)and(14 3 6 5)play a critical and leading role in the transition from liquid to glass.The nano-clusters formed in the system consist of some basic clusters and middle cluster configurations by connecting to each other,and distinguish from those obtained by gaseous deposition and ionic spray.From the results of structural parameter pair distribution function g(r),bond-types and basic cluster-types,it is found that the glass transition temperature Tg for liquid metal Cu is about 673 K at the cooling rate of 1.0×1014 K/s.展开更多
文摘Within the framework of the embedded-atom method, we performed molecular-dynamics calculations to investigate the structural transformation during melting of two copper clus- ters containing 57 and 58 atoms. The simulation results reveal how their different structural changes can strongly influence internal energy and radial distribution functions. The local structural patterns of different regions during the temperature increase, determined by atom density profiles, are identified for the melting of each cluster. The simulations show sensi- tivities of the structural changes for these two small size clusters with different structures.
基金This study was financially supported by the National Natural Science Foundation of China (No.50431030).
文摘With the Voter-Chen version of embedded-atom model （EAM） potential and molecular dynamics, the melting of Ni3Al alloy was simulated by one-phase （conventional） and two-phase approaches. It is shown that the simulated melting point is dependent on the potential and the simulation method. The structures of the melts obtained by different simulation methods were analyzed by the pair correlation function, the coordination number, and the distribution of atom pair type （indexed by the Honeycutt-Andersen pair analysis technique）. The results show that the structures are very similar.
文摘We report on molecular dynamics simulations performed using microcanonical ensemble to predict the melting of argon particles in nanometer size range 10 nm and to investigate the effect of the time step integration. We use the Lennard- Jones potential functions to describe the interatomic interactions, and the results are evaluated by using caloric curves of the melting phenomenon. Thermodynamic properties, including the total energy, Lindemann parameter, kinetic and potential distribution’s functions, are used to characterize the melting process. The data shows bimodal behavior only in a certain interval of integration time step Δt, while the internal energy increases monotonically with the temperature. For the other time step values, the back bending disappears. We claim that negative specific heat is related to a possible decrease of entropy in an isolated system;this can be interpreted as a result of the internal interactions, especially attractive process and specific relaxation time.
基金Projects(5027102650571037)supported by the National Natural Science Foundation of China
文摘Based on the quantum Sutton-Chen many-body potential,a molecular dynamics simulation was performed to investigate the formation and evolution properties of clusters in liquid Cu with 50 000 atoms.The cluster-type index method(CTIM)was used to describe the complex microstructure transitions.It is demonstrated that the amorphous structures are mainly formed with the three bond-types of 1551,1541 and 1431 in the system,and the icosahedral cluster(12 0 12 0)and other basic polyhedron clusters of(12 2 8 2),(13 1 10 2),(13 3 6 4),(14 1 10 3),(14 2 8 4)and(14 3 6 5)play a critical and leading role in the transition from liquid to glass.The nano-clusters formed in the system consist of some basic clusters and middle cluster configurations by connecting to each other,and distinguish from those obtained by gaseous deposition and ionic spray.From the results of structural parameter pair distribution function g(r),bond-types and basic cluster-types,it is found that the glass transition temperature Tg for liquid metal Cu is about 673 K at the cooling rate of 1.0×1014 K/s.
