1.IntroductionRecently Daw and Baskes[1,2]proposed the embedded atom model(EAM)on the basisof quasi-atom concept[3]and density-function theory.It is applicable to the transition met-als as well as the simple metals.It...1.IntroductionRecently Daw and Baskes[1,2]proposed the embedded atom model(EAM)on the basisof quasi-atom concept[3]and density-function theory.It is applicable to the transition met-als as well as the simple metals.It has been widely used in point defect[4],surface[5]andthermal expansion[6].Foiles[7]made the application of the EAM to liquid transition metalsand showed that the EAM also provided a realistic description of the energetics and structure展开更多
Persistent slip band （PSB） is an important and typical microstructure generated during fatigue crack initiation. Intensive work has been done to investigate the mechanisms of the formation of persistent slip bands s...Persistent slip band （PSB） is an important and typical microstructure generated during fatigue crack initiation. Intensive work has been done to investigate the mechanisms of the formation of persistent slip bands since the 1950s when Wadsworth[1] observed the fatigue fracture in copper. Simulations have indicated that PSBs formation during fatigue crack initiation is related to the dislocation driving force and interaction. In this paper, a molecular dynamics （MD） simulation associated with embedded atom model （EAM） is applied to the PSBs formation in nickel-base superalloys with different microstructure and temperature under tensile- tensile loadings. Five MD models with different microstructure （pure 5/ phase and γ/γ＇ phase）, grain orientation （[1 0 0][0 1 0][0 0 1] and [1 1 1][1 0 1][1 2 1]） and simulation temperature （300 K, 600 K, 900 K） were built up in these simulations. Our results indicated that within the γ phase by massive dislocations, pile-up and propagation which can penetrate the grain. Also, it is found that the temperature will affect the material fatigue performance and blur PSBs appearance. The simulation results are in strong agreement with published experimental test result. This simulation is based on the work[2]. The highlights of the article include： 1） investigation of the PSB formation via molecular dynamics simulation with three different parameters, 2） conduct of a new deformation and velocity combination controlled simulation for the PSB formation, 3） high-performance computing of PSB formation, and 4） systematic analysis of the PSB formation at the atomic scale in which the dislocation plays a critical role.展开更多
文摘1.IntroductionRecently Daw and Baskes[1,2]proposed the embedded atom model(EAM)on the basisof quasi-atom concept[3]and density-function theory.It is applicable to the transition met-als as well as the simple metals.It has been widely used in point defect[4],surface[5]andthermal expansion[6].Foiles[7]made the application of the EAM to liquid transition metalsand showed that the EAM also provided a realistic description of the energetics and structure
基金supported by School of Engineering and Built Environment,Glasgow Caledonian University,National Natural Science Foundation of China(Nos.51405044,51105061 and 11472075)the EPSRC funded ARCHIE-WESt high-performance computer(www.archie-west.ac.uk)(No.EP/K000586/1)
文摘Persistent slip band （PSB） is an important and typical microstructure generated during fatigue crack initiation. Intensive work has been done to investigate the mechanisms of the formation of persistent slip bands since the 1950s when Wadsworth[1] observed the fatigue fracture in copper. Simulations have indicated that PSBs formation during fatigue crack initiation is related to the dislocation driving force and interaction. In this paper, a molecular dynamics （MD） simulation associated with embedded atom model （EAM） is applied to the PSBs formation in nickel-base superalloys with different microstructure and temperature under tensile- tensile loadings. Five MD models with different microstructure （pure 5/ phase and γ/γ＇ phase）, grain orientation （[1 0 0][0 1 0][0 0 1] and [1 1 1][1 0 1][1 2 1]） and simulation temperature （300 K, 600 K, 900 K） were built up in these simulations. Our results indicated that within the γ phase by massive dislocations, pile-up and propagation which can penetrate the grain. Also, it is found that the temperature will affect the material fatigue performance and blur PSBs appearance. The simulation results are in strong agreement with published experimental test result. This simulation is based on the work[2]. The highlights of the article include： 1） investigation of the PSB formation via molecular dynamics simulation with three different parameters, 2） conduct of a new deformation and velocity combination controlled simulation for the PSB formation, 3） high-performance computing of PSB formation, and 4） systematic analysis of the PSB formation at the atomic scale in which the dislocation plays a critical role.
