Maintaining nano-lamellar microstructure in friction stir welding （FSW） of accumulative roll bonded （ARB） Cu-Nb nano-lamellar composites （NLC）
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2018年第1期
论文作者：Judy Schneider Josef Cobb John S.Carpenter Nathan A.Mara
文章页码：92 - 101
摘 要：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.
Judy Schneider1，Josef Cobb2，John S.Carpenter3，Nathan A.Mara4
1. Department of Mechanical & Aerospace Engineering, University of Alabama in Huntsville2. Department of Mechanical Engineering, Mississippi State University3. Materials Science and Technologies Division, Los Alamos National Laboratory4. Center for Integrated Nanotechnologies, and the Institute for Materials Science,Los Alamos National Laboratory
摘 要：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.
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