Fabrication And Reserch Of Aluminum Matrix Composites Used In Electronic Package

Materials used in electronic package field demand for high TC andlow CTE, as well as high strength and relatively low density, in order tomeet the demand of encapsulation. Metal matrix composites show goodperformance through adjusting the proportion of reinforcement andmatrix. In this paper, high volume fraction SiC/Al and Diamond/Alcomposites were researched to meet the demand in electronic package.Through the grading of SiC particles (F320:#1000=2:1) and thegel-casting method, volume fraction of SiC preform up to60%wasprepared, the distribution of SiC were uniform. The size of SiC preformwas stability after sintering and also with good quality. The strength ofpreform meet the requirement of subsequent processing and infiltration.Finally volume fraction of60%,55%,50%SiC preform were prepared.SiC/Al(AC4C) composites (60vol%,55vol%,50vol%) andDiamond/Al (99.99%purity) composites (40vol%including35、85、135μm grinding grade diamond and115μm MBD4grade diamond) wereprepared through vacuum pressure infiltration method, with the750℃ molten aluminum and680℃preform holding temperature, theinfiltration pressure was10MPa of nitrogen, then furnace cooling.The distribution of particles in SiC/Al prepared above were uniformand with good interface. The thickness of bonding layer was300nmaround, with little Al4C3formed on the interface. A majority of large SiCparticles were fractured through the observing of fractograph, also aminority of ductile fracture of aluminum matrix around the small particles.Mechanical performance of SiC/Al was good, bending strength of the55vol%SiC/Al reached to301.63MPa, which was the highest among theall. CTE decreased with the increase of SiC volume fraction,corresponding to8.99,9.5,10.04×10-6K-1(30℃-150℃). TC increasedwith the increase of SiC volume fraction, the highest reached to133W/m K corresponding to the60vol%SiC/Al.Diamond/Al was sick in the interface bonding, especially thegrinding grade diamond. The (100) face of MBD4grade diamond wasinclined to combine with the aluminum. TC was increased with theincrease of particle size, and the same law with CTE. Due to the goodbonding of (100) face, MBD4grade Diamond/Al perform the best inthermal properties, with TC of136W/m K and CTE of6.86×10-6K-1.