(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China; 2. Sino-German Cooperation Group “Microstructure in Al alloys”, Central South University, Changsha 410083, China; 3. CHINALCO Research Institute of Science and Technology, Beijing 102209, China; 4. School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Materials Genome Initiative is one of the routes towards high-efficiency design of aluminum alloys, to which quantitative structure characterization is the indispensable input and verification. As in the case for Al alloys, the quantitative micro- and nano- structure characterization includes the accurate and high-precision determination of not only crystal structures and the corresponding compositions, but also that of key structure parameters such as the sizes, number densities and volume fractions of phases. This paper takes the example of Al-Mg-Si(-Cu) alloy and summarizes the applications of various techniques to quantitative micro- and nano- structure characterization in Al alloys. Firstly, it is pointed out that advanced techniques such as high-resolution transmission electron microscopy, high angle annular dark firld and annular bright field scanning transmission electron microscopy show apparent advantages in investigating the atomic scale structure of nano-precipitates in Al alloys, meanwhile they display the high risk of electron beam damage; 3-dimensional atom probe fits very well the demands for accurate and precise compositional determination of atomic clusters and nano-precipitates but is destructive and is restricted by the small specimen volume and the quasi-nano spatial resolution; selected area electron diffraction is complementary to them, and more attention should be paid to the low-voltage low-dose high resolution TEM study. On the other hand, most recently an accurate, precise and facile method has been established for the determination of precipitate volume fraction based on convergent beam electron diffraction. Lastly, it has been predicted that the coupling of the above mentioned nano- to atomic- scale structure characterization techniques with the micro- to nano- scale characterization techniques such as focused ion beam serial sectioning, electron tomography and X-ray nano-tomography in the multi-procedure multi-scale quantitative structure characterization of Al alloys, as well as the incorporation of dynamic structure characterization by in-situ heating TEM observation, are possible trends in future Al alloy studies.