Concentrated solid-solution alloys(CSAs)based on 3d transition metals have demonstrated extraordinary mechanical properties and radiation resistance associated with their low stacking fault energies(SFEs).Owing to the...Concentrated solid-solution alloys(CSAs)based on 3d transition metals have demonstrated extraordinary mechanical properties and radiation resistance associated with their low stacking fault energies(SFEs).Owing to the intrinsic disorder,SFEs in CSAs exhibit distributions depending on local atomic configurations.In this work,the distribution of SFEs in equiatomic CSAs of NiCo,NiFe,and NiCoCr are investigated based on empirical potential and first-principles calculations.We show that the calculated distribution of SFEs in chemically disordered CSAs depends on the stacking fault area using empirical potential calculations.Based on electronic structure calculations,we find that local variations of SFEs in CSAs correlate with the charge density redistribution in the stacking fault region.We further propose a bond breaking and forming model to understand and predict the SFEs in CSAs based on the local structure alone.It is shown that the perturbation induced by a stacking fault is localized in the first-nearest planes for NiCo,but extends up to the third nearest planes for NiFe and NiCoCr because of partially filled d electrons in Fe and Cr.展开更多
We study the K-state phenomenon in the NiCoCr medium-entropy alloy using first-principles techniques jointly with the efficient Wang–Landau Monte Carlo and simulated annealing algorithms.Our theoretical results succe...We study the K-state phenomenon in the NiCoCr medium-entropy alloy using first-principles techniques jointly with the efficient Wang–Landau Monte Carlo and simulated annealing algorithms.Our theoretical results successfully explain the existence of the peak around 940 K in the experimental specific heat curve that characterizes the K-state phenomenon and give a fine picture of its atomic origin.The peak is caused by the maximum change of the local configurations characterized by the short-range-order(SRO)parameters at that temperature.展开更多
基金This work was supported as part of the Energy Dissipation to Defect Evolution(EDDE),an Energy Frontier Research Center funded by the US Department of Energy,Office of Science,Basic Energy Sciences under contract number DE-AC05-00OR22725.
文摘Concentrated solid-solution alloys(CSAs)based on 3d transition metals have demonstrated extraordinary mechanical properties and radiation resistance associated with their low stacking fault energies(SFEs).Owing to the intrinsic disorder,SFEs in CSAs exhibit distributions depending on local atomic configurations.In this work,the distribution of SFEs in equiatomic CSAs of NiCo,NiFe,and NiCoCr are investigated based on empirical potential and first-principles calculations.We show that the calculated distribution of SFEs in chemically disordered CSAs depends on the stacking fault area using empirical potential calculations.Based on electronic structure calculations,we find that local variations of SFEs in CSAs correlate with the charge density redistribution in the stacking fault region.We further propose a bond breaking and forming model to understand and predict the SFEs in CSAs based on the local structure alone.It is shown that the perturbation induced by a stacking fault is localized in the first-nearest planes for NiCo,but extends up to the third nearest planes for NiFe and NiCoCr because of partially filled d electrons in Fe and Cr.
基金This research used resources of the Oak Ridge Leadership Computing Facility,which is supported by the Office of Science of the U.S.Department of Energy under Contract No.DE-AC05-00OR22725M.C.G.acknowledges the support of the US Department of Energy’s Fossil Energy Crosscutting Technology Research Program at National Energy Technology Laboratory under the RSS contract 89243318CFE000003.
文摘We study the K-state phenomenon in the NiCoCr medium-entropy alloy using first-principles techniques jointly with the efficient Wang–Landau Monte Carlo and simulated annealing algorithms.Our theoretical results successfully explain the existence of the peak around 940 K in the experimental specific heat curve that characterizes the K-state phenomenon and give a fine picture of its atomic origin.The peak is caused by the maximum change of the local configurations characterized by the short-range-order(SRO)parameters at that temperature.
