Study On Fabrication And Properties Of Sip/Al Composites

As with the high thermal conductivity, low thermal expansion coefficient, lowdensity, and processability etc, Sip/Al composites show great promise in the field ofelectronic packaging. Sip/Al composites were fabricated by pressureless infiltration.The effect of process parameters on microstructure and the relative density of theSip/Al composites were analyzed. Solidification microstructure of composites bypressureless infiltration was investigated. The effect of Si particle size, matrix alloy,process parameters and Si volume fraction on thermophysical and mechanicalproperties of Sip/Al composites were studied.The results show that the microstructure of Sip/Al composites fabricated bypressureless infiltration is dense and uniform. In the same infiltration time, along withthe increasing infiltration temperature, Si particles from irregular shape, evolved intosharp disappeared and the particles connect with each other. Finally, silicon particleshape shows obvious changing, almost Si are forming network configuration. With theinfiltration temperature and time increasing, the relative density of Sip/Al compositesincreases.The microstructure of Al-Si matrix alloy in the interspace of Si phase is notypical primary phase and eutectic microstructure. There is a phenomenon similar tothe separate-eutectic microstructure. Primary Si phase and eutectic Si phase crystallizeand grow at origin Si phase. The interface of Sip/Al composites bonding well, XRDanalyzing shows that there are Si phase and Al phase and no compound is found incomposites.With Si particle size increasing, the thermal conductivity and thermal expansioncoefficient of Sip/Al composites were increases，while bending strength decreases. Inthe same condition, the thermal conductivity and thermal expansion coefficient ofSip/Al composites that pure aluminum1060as matrix are higher than ZL102asmatrix. The bending strength is lower than ZL102as matrix of the composites.With infiltration temperature and infiltration time increasing, the thermalconductivity, the thermal expansion coefficient and bending strength of Sip/Alcomposites decreases. With the increasing of Si volume fraction, the bending strengthof Sip/Al composites increases, the thermal conductivity and the thermal expansioncoefficient of composites decreases. Toughness dimples appear in the fracture of the Sip/Al composites.Cleavagefracture were occurred from Si particles.Brittle rupture is still major character in thefracture.