Accumulative roll bonded (ARB) Copper Niobium (Cu-Nb) nano-lamellar composite (NLC) panels were friction stir welded (FSWed) to evaluate the ability to join panels while retaining the nano-lamellar structure. During a single pass of the friction stir welding (FSW) process, the nano-lamellar structure of the parent material (PM) was retained but was observed to fragment into equiaxed grains during the second pass. FSW has been modeled as a severe deformation process in which the material is subjected to an instantaneous high shear strain rate followed by extreme shear strains. The loss of the nano-lamellar layers was attributed to the increased strain and longer time at temperature resulting from the second pass of the FSW process. Kinematic modeling was used to predict the global average shear strain and shear strain rates experienced by the ARB material during the FSW process. The results of this study indicate that through careful selection of FSW parameters, the nano-lamellar structure and its associated higher strength can be maintained using FSW to join ARB NLC panels.
Bibliographical noteFunding Information:
This work was supported by the Los Alamos National Laboratory Directed Research and Development (LDRD) project 20130764ECR . This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Los Alamos National Laboratory, an affirmative action equal opportunity employer, is operated by Los Alamos National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy under contract DE-AC52-06NA25396. Electron microscopy was performed at the Los Alamos Electron Microscopy Laboratory.
- Accumulative roll bonded
- Nano-lamellar materials
- Solid state joining