TY - JOUR
T1 - Microstructural stability of nanostructured Cu-Nb-W alloys during high-temperature annealing and irradiation
AU - Zhang, X.
AU - Vo, N. Q.
AU - Bellon, P.
AU - Averback, R. S.
N1 - Funding Information:
This research was supported by the US DOE-BES under Grant DEFG02-05ER46217 (supporting NQV) and by the NSF under Grant DMR 08-04615 (supporting XZ). The work was carried out in part in the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois, which are partially supported by the US Department of Energy under grants DE-FG02-07ER46453 and DE-FG02-07ER46471. The authors thank Dr J.G. Wen for his assistance with aberration-corrected TEM characterization.
PY - 2011/8
Y1 - 2011/8
N2 - The microstructural evolution of dilute Cu-based ternary Cu-Nb alloys during high-temperature annealing was investigated using a combination of transmission electron microscopy, X-ray diffraction and kinetic Monte Carlo (KMC) simulations. The experiments showed that, during annealing, the Cu 90Nb10 binary alloy undergoes extensive coarsening at 600 °C, with precipitate sizes increasing to >40 nm. Additions of just 1.5 at.% W to this alloy, however, dramatically suppresses the growth; the average precipitate size in the ternary alloy now increases to only ∼10 nm at 600 °C, and only to 18 nm at 700 °C. On annealing at still higher temperatures, the precipitate size then, surprisingly, decreases. The precipitate size distribution at the higher temperatures, moreover, is bimodal. It is also observed that irradiation has no effect on the microstructure of the ternary alloys above 600 °C. KMC simulations indicate that the saturation of the average precipitate size, followed by its decrease as the annealing temperature is increased and the development of a bimodal size distribution can be explained by competition between thermodynamic and kinetic effects during precipitation in this ternary alloy.
AB - The microstructural evolution of dilute Cu-based ternary Cu-Nb alloys during high-temperature annealing was investigated using a combination of transmission electron microscopy, X-ray diffraction and kinetic Monte Carlo (KMC) simulations. The experiments showed that, during annealing, the Cu 90Nb10 binary alloy undergoes extensive coarsening at 600 °C, with precipitate sizes increasing to >40 nm. Additions of just 1.5 at.% W to this alloy, however, dramatically suppresses the growth; the average precipitate size in the ternary alloy now increases to only ∼10 nm at 600 °C, and only to 18 nm at 700 °C. On annealing at still higher temperatures, the precipitate size then, surprisingly, decreases. The precipitate size distribution at the higher temperatures, moreover, is bimodal. It is also observed that irradiation has no effect on the microstructure of the ternary alloys above 600 °C. KMC simulations indicate that the saturation of the average precipitate size, followed by its decrease as the annealing temperature is increased and the development of a bimodal size distribution can be explained by competition between thermodynamic and kinetic effects during precipitation in this ternary alloy.
KW - Copper alloys
KW - Monte Carlo techniques
KW - Precipitation
KW - Transmission electron microscopy
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U2 - 10.1016/j.actamat.2011.05.009
DO - 10.1016/j.actamat.2011.05.009
M3 - Article
AN - SCOPUS:79959517817
SN - 1359-6454
VL - 59
SP - 5332
EP - 5341
JO - Acta Materialia
JF - Acta Materialia
IS - 13
ER -