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Physical Vapor Deposition nano-multilayered composites of Copper and Niobium have demonstrated extraordinary ability to withstand both mechanical- and radiation-induced damage nucleation when the layer thicknesses are <1 µ. Although the bimetallic interfaces are believed to play a role in the enhanced performance, we have yet to demonstrate thorough explanations for these observed performance enhancements. There is a desire to scale the manufacture of this class of materials to commercially viable processes. For this reason, the accumulated roll bonding process has been developed to manufacture these layered composite materials. During this process, the individual Copper (FCC) and Niobium (BCC) layer thicknesses begin at 1 mm and continue until the layer thicknesses become on the order of 10s of nanometers. We present a new local single crystal model for the potential influence of the bimaterial interface on dislocation motion in the near vicinity of the interface and apply this model to polycrystal multilayer simulations in an attempt to predict the dominant experimentally observed orientation relationships across the interface. Simple compression and nanoindentation mechanical test results have been used to characterize each of the material model parameter sets. These simulations employ statistically equivalent polycrystal structures as representation of the experimentally characterized individual composite layers. Calculations for the purpose of predicting the evolution of crystallographic texture in these layered composite materials will be presented. Calculations of orientation relationship stability of experimentally observed dominant interface relationships will also be presented and potential hypotheses for these observations will be made. We will also present results of interface orientation relationships across the interface and their evolution. We will also show results suggesting that the stability of interface morphology is a direct result of reduced numbers of grains through the thickness of the individual layers. Direct comparison of numerical results to experimental results will be made to the fullest extent possible.

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Modeling the interface formation and morphology within Cu/Nb layered composites by accumulated roll bonding

Physical Vapor Deposition nano-multilayered composites of Copper and Niobium have demonstrated extraordinary ability to withstand both mechanical- and radiation-induced damage nucleation when the layer thicknesses are <1 >µ. Although the bimetallic interfaces are believed to play a role in the enhanced performance, we have yet to demonstrate thorough explanations for these observed performance enhancements. There is a desire to scale the manufacture of this class of materials to commercially viable processes. For this reason, the accumulated roll bonding process has been developed to manufacture these layered composite materials. During this process, the individual Copper (FCC) and Niobium (BCC) layer thicknesses begin at 1 mm and continue until the layer thicknesses become on the order of 10s of nanometers. We present a new local single crystal model for the potential influence of the bimaterial interface on dislocation motion in the near vicinity of the interface and apply this model to polycrystal multilayer simulations in an attempt to predict the dominant experimentally observed orientation relationships across the interface. Simple compression and nanoindentation mechanical test results have been used to characterize each of the material model parameter sets. These simulations employ statistically equivalent polycrystal structures as representation of the experimentally characterized individual composite layers. Calculations for the purpose of predicting the evolution of crystallographic texture in these layered composite materials will be presented. Calculations of orientation relationship stability of experimentally observed dominant interface relationships will also be presented and potential hypotheses for these observations will be made. We will also present results of interface orientation relationships across the interface and their evolution. We will also show results suggesting that the stability of interface morphology is a direct result of reduced numbers of grains through the thickness of the individual layers. Direct comparison of numerical results to experimental results will be made to the fullest extent possible.