Study on Pseudo-Eutectic Region and Mechanical Properties of Pseudo-Eutectic Microstructure of Al–Si Alloys

In the present work, the boundary points of the left and right composition points in the pseudo-eutectic region of Al–Si alloys are determined by analyzing the microstructure of Al–Si alloys with different silicon content solidified at constant temperature. By analyzing the microstructure of Al–Si alloys with the same content solidified at different temperatures, the upper and lower temperature boundary points of the pseudo-eutectic region are determined. Then, Origin software is used to fit all the measurement results of the boundary points of the pseudo-eutectic region, and the pseudo-eutectic region of Al–Si alloys is obtained. The microhardness of the pseudo-eutectic structure was tested using a Vickers hardness tester, and the results show that the microhardness of the pseudo-eutectic structure is significantly higher than that of the eutectic structure in ordinary cast Al–Si alloys when silicon content is the same. As the silicon content increases, the microhardness of the pseudo-eutectic structure continues to increase.