Diffusion of Zn in nanostructured aluminum alloys produced by surface mechanical attrition treatment

Chang, H. W., Kelly, P. M., Shi, Y. N. and Zhang, M. X. (2012) Diffusion of Zn in nanostructured aluminum alloys produced by surface mechanical attrition treatment. Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science, 43A 7: 2378-2389. doi:10.1007/s11661-012-1112-x


Author Chang, H. W.
Kelly, P. M.
Shi, Y. N.
Zhang, M. X.
Title Diffusion of Zn in nanostructured aluminum alloys produced by surface mechanical attrition treatment
Journal name Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science   Check publisher's open access policy
ISSN 1073-5623
1543-1940
Publication date 2012-07-01
Sub-type Article (original research)
DOI 10.1007/s11661-012-1112-x
Volume 43A
Issue 7
Start page 2378
End page 2389
Total pages 12
Place of publication New York, United States
Publisher Springer New York
Language eng
Abstract After surface nanocrystallization of pure Al and a cast Al-Si alloy through surface mechanical attrition treatment (SMAT), 200- to 300-lm-thick Zn coatings were deposited on the nanostructured surface using the clod spray technique. Subsequently, diffusion of Zn into the Al substrate was induced by postspray annealing treatment at various temperatures for different times. The diffusion kinetics of Zn in the nanostructured surface layers was studied in terms of the Zn concentration profile in the substrate by using scanning electron microscopy (SEM) and electron probe microscopy analysis (EPMA). Experimental results show that not only the diffusivity of Zn in the nanocrystalline grains is significantly increased compared with the diffusion in the coarse grained counterpart, but the temperature at which noticeable Zn diffusion in Al alloys occurs is also reduced from 573 K (300 °C) in coarse-grained Al alloys to 523 K (250 °C) in nanostructured alloys. In addition, because the nanocrystalline grains produced by SMAT in Al-Si alloys are much smaller than those in pure Al due to the effect of eutectic Si, the diffusion of Zn in the SMATed Al-Si alloy is much faster than that in the SMATed pure Al. It is believed that the high diffusivity of Zn in the nanocrystalline Al grains is attributed to the large fraction of grain boundaries that act as fast diffusion channel. The effect of thermal stability of the nanocrystalline grains on Zn diffusion in the SMATed Al alloys is also discussed.
Keyword Cold spray coatings
Nanocrystalline copper
Nickel
Layers
Iron
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Article published online: April 14, 2012.

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mechanical & Mining Engineering Publications
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