Orientation and Microstructure Evolution of Al-Al2Cu Regular Eutectic Lamellar Bifurcating in an Abruptly Changing Velocity under Directional Solidification

Ka Gao; Zan Zhang; Junliang Zhao; Dejian Sun; Fu Wang

doi:10.3390/ma13041004

Orientation and Microstructure Evolution of Al-Al₂Cu Regular Eutectic Lamellar Bifurcating in an Abruptly Changing Velocity under Directional Solidification

Materials (Basel). 2020 Feb 24;13(4):1004. doi: 10.3390/ma13041004.

Authors

Ka Gao^{1

2}, Zan Zhang^{1

2}, Junliang Zhao^{1

2}, Dejian Sun^{1

2}, Fu Wang³

Affiliations

¹ School of Materials Science and Engineering, Zhengzhou University of Aeronautics, Zhengzhou 450015, China.
² Henan Key Laboratory of Aeronautical Material and Application Technology, Zhengzhou 450015, China.
³ School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.

Abstract

In an abruptly changing velocity under directional solidification, microstructures and the growth orientation of Al-Al₂Cu eutectic lamellar were characterized. The change in solidification rate led to an interfacial instability, which results in a bifurcation of the eutectic lamella into new, refined lamellae. The growth orientation of the eutectic Al₂Cu phase was also only in its (001) direction and more strongly oriented to the heat flow direction. The results suggest that the eutectic lamellar Al-Al₂Cu bifurcation and the spacing adjustment may be caused by the rate determining lateral diffusion of the solutes after interfacial instability.

Keywords: directional solidification; grain growth; growth orientation; lamellar bifurcation; solidification rate.

Abstract

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