Through gravity casting and isothermal heat treatment combined with hot extrusion method

the Mg

2

Si/Al composites for aviation electron were prepared and investigated.Effects of different isothermal holding time and isothermal temperature on the microstructure and mechanical properties of the composites prepared were analyzed

and the mechanism was described.The results show that the Mg

2

Si phase is converted from small polygonal to spheroidiation or ellipsoid shape after isothermal heat treatment

and the degree of spheroidization is gradually increased with the isothermal time increase.The tensile strength and elongation of semi-solid squeezed Mg

2

Si/Al composites are superior to those of gravity casting Mg

2

Si/Al composite after different isothermal temperatures and time.The fracture of Mg

2

Si/Al composites is characterized mainly by matrix fracture

primary Mg

2

Si phase cracking and primary Mg

2

Si phase with matrix interface debonding.