Quantitative measurement for the microstructural parameters of nano-precipitates in Al-Mg-Si-Cu alloys
(2016) Materials Characterization — Vol. 118, p. 352-362 (2016)
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- Abstract
- Size, number density and volume fraction of nano-precipitates are important microstructural parameters controlling the strengthening of materials. In this work a widely accessible, convenient, moderately time efficient method with acceptable accuracy and precision has been provided for measurement of volume fraction of nano-precipitates in crystalline materials. The method is based on the traditional but highly accurate technique of measuring foil thickness via convergent beam electron diffraction. A new equation is proposed and verified with the aid of 3-dimensional atom probe (3DAP) analysis, to compensate for the additional error resulted from the hardly distinguishable contrast of too short incomplete precipitates cut by the foil surface. The method can be performed on a regular foil specimen with a modern LaB6 or field-emission-gun transmission electron microscope. Precisions around ±16% have been obtained for precipitate volume fractions of needle-like β″/C and Q precipitates in an aged Al-Mg-Si-Cu alloy. The measured number density is close to that directly obtained using 3DAP analysis by a misfit of 4.5%, and the estimated precision for number density measurement is about ±11%. The limitations of the method are also discussed.
- Affiliations
Central South University School of Metallurgy and Environment University of Antwerp Electron Microscopy for Materials Science Central South University State Key Laboratory of Powder Metallurgy Nanjing University of Science and Technology Gleiter Institute of Nano-science Xi'an Jiaotong University Electronic Materials Research Laboratory ArcelorMittal Global R and D The University of Sydney Australian Institute for Nanoscale Science and Technology The University of Sydney School of Aerospace, Mechanical and Mechatronic Engineering
Citations
Li, K., Idrissi, H., Sha, G., Song, M., Lu, J., Shi, H., Wang, W., Ringer, S. P., Du, Y., & Schryvers, D. (2016). Quantitative measurement for the microstructural parameters of nano-precipitates in Al-Mg-Si-Cu alloys. Materials Characterization, 118, 352-362. https://doi.org/10.1016/j.matchar.2016.06.007 (Original work published 2016)