Study On Centrifugal Casting Process Of The SiC Particle Reinforced Aluminum Matrix Composites For Electronic Packaging

The fabrication and centrifugal casting forming of SiC particle-reinforced composites parts were studyed deeply,and the effects of process parameters on the microstructure, composition and properties of composites were also researched systemically, and the characteristic of processing, microstructure and mechanical properties were illustrated widely, which are all under pressureless infiltration for electronic packaging applications.From the view of industrial production, fabricate two composite materials: the fabrication of SiC particle reinforced Zl104 composites is researched deeply, in which the volume fraction of SiC particles is 17.55 percent, and the average diameter is 15μm,30μm,51μm,and the mass of composites arrive to 18Kg in one cycle. In addition, the other fabrication of SiC particle reinforced Zl109 composites is researched deeply, in which the volume fraction SiC particles is 24 percent, and the average diameter is 25μm,29μm,120μm,and the mass of composites arrive to 18Kg in one cycle.Base on the wettability between SiC particles and aluminum Molten, the proess parameters of composite materials was studyed. Study shows that the best temperature for the wettalility is 575±3℃, and at this temperature the frabrication of the composite materials performed best.Considering the design of the centrifugal casting process, two matrix of SiC particles in aluminum matrix composites for electronic packaging box parts were prepared by the mold and sand core designed by oneself. When the speed was 800r/min, the molten were poured at the temperature 700℃and molten parts were sanpled then. The microstructures of the SiCp/Al compenent were observed and analyzed through OM and SEM. The SiC particles volume content of the sample were tested by testing density and anaysing the image. The CTE of the sample was tested by thermal expansion arraratus. Factors which influent CTE were also analysised.The effect of SiC particle segregation in the SiCp / Al composites which fabricated by study was obvious .There are three region in the section of casting: segregation particle layer, no particle layer and squeezings region. The sample was separated by casting the segregation particle layer and no particle layer. The surface of the parts were very clear, and had no traditional casting defects. Through the OM and SEM, the sample had a compact structure and no obvious defects compared with the traditional parts, and SiC particles distribution were stable. Besides, the wetting of the liquid interface of the SiC particles and aluminum were excellent. Density testing results show that the volume fraction of SiC particles of composite A is 23%, the volume fraction of SiC particles of composite B is 39%, which are all enhanced greatly than the composite materials fabracted centrifugal casting. A materials was increased by 35.2%, B material was increased by 60%. Results show that the separation between the SiC particles and the molten aluminum achieved by centrifugal casting were successful. Imgaetool testing results show that the volume fraction of SiC particles of B composite is 46%. The CTE of the composite material B is 9.90×10^-6K^-1, which meet the basis request for the use of electronic packing .