The striking variation in damage tolerance among refractory complex concentrated alloys is examined through the analysis of atomistic fracture simulations,contrasting behavior in elemental Nb with that in brittle NbMo...The striking variation in damage tolerance among refractory complex concentrated alloys is examined through the analysis of atomistic fracture simulations,contrasting behavior in elemental Nb with that in brittle NbMoTaW and ductile Nb_(45)Ta_(25)Ti_(15)Hf_(15).We employ machine-learning interatomic potentials(MLIPs),including a new MLIP developed for NbTaTiHf,in atomistic simulations of crack tip extension mechanisms based on analyses of atomistic fracture resistance curves.While the initial behavior of sharp cracks shows good correspondence with the Rice theory,fracture resistance curves reveal marked changes in fracture modes for the complex alloys as crack extension proceeds.In NbMoTaW,compositional complexity appears to promote dislocation nucleation relative to pure Nb,despite theoretical predictions that the alloy should be relatively more brittle.In Nb_(45)Ta_(25)Ti_(15)Hf_(15),alloying alters the fracture mode compared to elemental Nb,promoting crack tip blunting and enhancing resistance to crack propagation.展开更多
基金supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Materials Sciences and Engineering Division,under Contract No.DE-AC02-05-CH11231 within the Damage Tolerance in Structural Materials(KC 13)programThe study made use of resources of the National Energy Research Scientific Computing Center(NERSC),a U.S.Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory,operated under the same contract number,using NERSC Award No.BES-ERCAP0027535This research used the Lawrencium computational cluster resource provided by the IT Division at the Lawrence Berkeley National Laboratory(Supported by the Director,Office of Science,Office of Basic Energy Sciences,of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231).The Scientific Computing Group(also known as High-Performance Computing Services)under Science IT supports the mission of Lawrence Berkeley National Laboratory by providing technology and consulting support for science and technical programs,in the areas of data management,HPC cluster computing,and Cloud services.
文摘The striking variation in damage tolerance among refractory complex concentrated alloys is examined through the analysis of atomistic fracture simulations,contrasting behavior in elemental Nb with that in brittle NbMoTaW and ductile Nb_(45)Ta_(25)Ti_(15)Hf_(15).We employ machine-learning interatomic potentials(MLIPs),including a new MLIP developed for NbTaTiHf,in atomistic simulations of crack tip extension mechanisms based on analyses of atomistic fracture resistance curves.While the initial behavior of sharp cracks shows good correspondence with the Rice theory,fracture resistance curves reveal marked changes in fracture modes for the complex alloys as crack extension proceeds.In NbMoTaW,compositional complexity appears to promote dislocation nucleation relative to pure Nb,despite theoretical predictions that the alloy should be relatively more brittle.In Nb_(45)Ta_(25)Ti_(15)Hf_(15),alloying alters the fracture mode compared to elemental Nb,promoting crack tip blunting and enhancing resistance to crack propagation.
