EBSD investigation of the effect of the solidification rate on the nucleation behavior of eutectic components in a hypoeutectic Al-Si-Cu alloy

• This article is devoted to a study of the influence of solidification rate on the crystallographic orientation of eutectic components with respect to primary α-Al in the tested hypoeutectic alloy. Electron backscattering diffraction (EBSD) patterns were produced from Al-Si cast specimens, solidified with different cooling rates, and prepared by ion etch polishing as a complementary method after mechanical polishing. Results indicated a strong orientation relationship between the primary α-Al and eutectic aluminum phase at all cooling rates. It is also found that the silicon eutectic flakes are nucleated heterogeneously in the interdendritic eutectic liquid. Increasing the cooling rate from 2 to 80 mm/min is observed to be effective in lowering the intensity of relationship between the primary α-Al and eutectic aluminum phase and changing the misorientation angle clustering between primary α-Al and eutectic silicon phase in the interval 41-60 to lower angle intervals.

Nyckelord

EBSD

Pole figure analysis

Al-Si alloy

Nucleation

Orientation relationship

TECHNOLOGY

TEKNIKVETENSKAP

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