Solute-Derived Thermal Stabilization of Nano-sized Grains in Melt-Spun Aluminum
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Thermal stabilization of nanograined metallic microstructures (or nanostructures) can be difficult due to the large driving force for growth that arises from the inherently significant boundary area. Kinetic approaches for stabilization of the nanostructure effective at low homologous temperatures often fail at higher homologous temperatures. Alternatively, thermodynamic approaches for thermal stabilization may offer higher temperature stability. In this research, modest alloying of aluminum with solute (1 pct by mole Sc, Yb, or Sr) was examined as a means to thermodynamically stabilize a bulk nanostructure at elevated temperatures. Following 1-hour annealing treatments at 673 K (400 °C) (0.72 Tm), 773 K (500 °C) (0.83 Tm), and 873 K (600 °C) (0.94 Tm), the alloys remain nanocrystalline (<100 nm) as measured by Warren–Averbach Fourier analysis of X-ray diffraction peaks and direct observation of TEM dark-field micrographs, with the efficacy of stabilization: Sr ≈ Yb > Sc. The disappearance of intermetallic phases in the Sr- and Yb-containing alloys in the X-ray diffraction spectra is observed to occur coincident with the stabilization after annealing, suggesting that precipitates dissolve and the boundaries are enriched with solute.
KeywordsAnnealing Treatment Boundary Energy Column Length Al3Sc Solute Segregation
The authors would like to acknowledge Paul Fraley (Michigan Technological University Particulates Processing Laboratory) for his assistance in melt-spinning sample preparation, Ed Laitila (Michigan Technological University Applied Chemical and Morphological Analysis Laboratory) for his assistance in X-ray diffraction analysis, and Owen Mills (Applied Chemical and Morphological Analysis Laboratory) for his assistance in TEM sample preparation.
The following copyright wording should be placed in the block with the author affiliations: E.A. Lass is employed by National Institute of Standards and Technology. U.S. Government work is not protected by U.S. Copyright.
- 13.J. Weissrmiller, J. Mater. Res., 1994, vol. 9.Google Scholar
- 17.A. Sutton, and R. Balluffi, Interfaces in Crystalline Solids, Clarendon: Oxford 1995Google Scholar
- 24.Liu, W. J., C. Sun, P. X. Zhao and S. F. Wang, Advanced Materials Research 2012, vol. 550, pp. 71-74.Google Scholar
- 25.Halder, N. and C. Wagner, Adv. X-ray Anal 1966, vol. 9, pp. 91-102.Google Scholar
- 28.B. Warren, and X.-R. Diffraction, New York, 1990, p. 251.Google Scholar
- 31.Abràmoff, M. D., P. J. Magalhães and S. J. Ram, Biophotonics international 2004, vol. 11, pp. 36-43.Google Scholar
- 33.Gibbons, J. D., Gibbons nonparametric methods for quantitative analysis, Holt, Rinehart and Winston: New York, 1976.Google Scholar
- 40.F. De Boer, R. Boom, W. Mattens, A. Miedema, and A. Niessen: Cohesion in Metals: Transition Metal Alloys: Cohesion and Structure. (North-Holland, Amsterdam, 1989).Google Scholar
- 42.Gale, W. F. and T. C. Totemeier: Smithells metals reference book. Butterworth-Heinemann, Oxford, 2003.Google Scholar
- 43.Lide, D. R.: CRC handbook of chemistry and physics. CRC press, Boca Raton, 2004.Google Scholar
- 48.P. Villars and K. Cenzual, Pearson’s crystal data—crystal structure database for inorganic compounds, release 2012/13 Materials Park, Ohio, USA, ASM International.Google Scholar