Effect of flow characteristics in the inner gate on the microstructure of a semi-solid processed hypereutectic Al–Si alloy

Abstract

ABSTRACTThis study aims to prepare hypereutectic Al–Si alloy cylindrical samples with hard inner surfaces by changing the depth of inner gates in squeeze casting molds. The characteristic parameters (volume fraction and equivalent diameter) of the hard phases (primary Si and Fe-rich phases) and the hardness of the samples were observed. When the depth of the inner gate is 5 mm, there is a radial gradient in the characteristic parameters of the hard phases in the members resulting in surface strengthening of the structural member. However, when the depth of the inner gate is 9 mm, there is no radial gradient. The mechanisms of achieving surface strengthening in hypereutectic Al–Si alloy cylindrical samples by changing the rheological characteristics of semi-solid Al–Si alloy slurries were revealed.

Keywords

• Hypereutectic Al–Si alloy
• rheological squeeze casting
• Inner surface strengthen
• semi-solid Al–Si alloy slurries