Investigation the solidified layer in compound casting the A390/A356 alloys

The cast-decant-cast is a new method in the functionally graded components process that has been developed in recent years. The functionally graded cylindrical shape component with a radial gradient e.g. the first alloy (A390) with high wear resistance on the surface of the piece and toughness and low machining costs of the second alloy (A356) in the core of the piece can be produced via this melt process. This paper has particularly investigated the effect of the first alloy solidified layer at 25, 35 and 45 seconds decanting time on achieving the perfect interface between the two alloys. The characterization of the interface was carried out by optical microscopy and scanning electron microscopy and its width was measured by the microhardness test. Results showed that the best interface is obtained at 860 oC and 35 seconds decanting time with a width of 500μm. Also, the wear resistance test was performed to measure and compare the surface wear resistance to the core.

Keywords:

A390 alloy , A356 alloy , functionally graded material , Cast-Decant-Cast process