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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/13089
Title: Thermodynamic feasibility of solid solubility extension of Nb in Cu and their thermal stability
Authors: Mula, Suhrit
Bahmanpour H.
Mal S.
Kang P.C.
Atwater M.
Jian W.
Scattergood R.O.
Koch C.C.
Published in: Materials Science and Engineering A
Abstract: A series of Cu- xNb (x= 1-15. at.%. 22All the compositions are expressed in at.% after this unless otherwise stated.) alloys have been investigated to study the metastable solid solubility extension of Nb in Cu by mechanical alloying. Analysis of X-ray diffraction and Gibbs free energy change confirmed that 7.5% of Nb was metastably dissolved in Cu after 8. h of milling at room temperature although Cu-Nb is a system with positive heat of mixing. The solid solubility could be extended up to 10% after enhancing milling duration to 16. h. Detailed thermodynamic analysis revealed that the additional energy stored during mechanical alloying could overcome the required energy barrier as per Miedema's model for the formation of disordered solid solution. The extended solid solubility has been explained along with the other possible mechanisms. Extensive annealing experiments and structural investigation revealed that the supersaturated solid solution is completely stable up to 400. °C. The matrix grains were stabilized and retained their size, ~25. nm, even after annealing at 600. °C. Microhardness measurement and grain size analysis show that the dissolution of Nb in Cu has a larger strengthening effect than that of free Nb in the compositions. © 2012 Elsevier B.V.
Citation: Materials Science and Engineering A (2012), 539(): 330-336
URI: https://doi.org/10.1016/j.msea.2012.01.104
http://repository.iitr.ac.in/handle/123456789/13089
Issue Date: 2012
Keywords: Metastable nanostructure
Microhardness
Thermal stability
Thermodynamic analysis
X-ray diffraction
ISSN: 9215093
Author Scopus IDs: 12783902100
36859235600
36160564100
7007182376
16315093500
54965793200
7006411003
57203364844
Author Affiliations: Mula, S., Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695, United States, Department of Metallurgical and Materials Engineering, National Institute of Technology, Rourkela 769008, India
Bahmanpour, H., Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695, United States
Mal, S., Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695, United States
Kang, P.C., Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695, United States
Atwater, M., Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695, United States
Jian, W., Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695, United States
Scattergood, R.O., Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695, United States
Koch, C.C., Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695, United States
Corresponding Author: Mula, S.; Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695, United States; email: smula@ncsu.edu
Appears in Collections:Journal Publications [MT]

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