High reinforcement content SiCp/Cu composites (φp=50%, 55% and 60%) for electronic packaging applications were fabricated by patent cost-effective squeeze-casting technology. The composites appear to be free of pores, and the SiC particles are distribute uniformly in the composites. The mean linear coefficients of thermal expansion (CTEs, 20-100 ℃ ) of as-cast SiCp/Cu composites range from 8.8×10-6 ℃-1 to 9.9×10-6 ℃-1 and decrease with the increase of SiC content. The experimental CTEs of as-cast SiCp/Cu composites agree well with the predicted values based on Kerner model. The CTEs of composites reduce after annealing treatment due to the fact that the internal stress of the composite is released. The Brinell hardness increases from 272.3 to 313.2, and the modulus increases from 186 GPa to 210 GPa for the corresponding composites. The bending strength is larger than 374 MPa, but no obvious trend between bending strength and SiCp content is observed.
Two micron SiC particles with angular and spherical shape and the sub-micron Al2O3 particles with spherical shape were introduced to reinforce 6061 aluminium by squeeze casting technology. Microstructures and effect of thermal-cooling cycle treatment （TCCT） on the thermal expansion behaviors of three composites were investigated. The results show that the composites are free of porosity and SiC/Al2O3 particles are distributed uniformly. Inflections at about 300℃ are observed in coefficient of thermal expansion （CTE） versus temperature curves of two SiCp/Al composites, and this characteristic is not affected by TCCT. The TCCT has significant effect on thermal expansion behavior of SiCp/Al composites and CTE of them after 3 cycles is lower than that of 1 or 5 cycles. However, no inflection is observed in Al2O3p/Al composite, while TCCT has effect on CTE of Al2O3p/Al composite. These results should be due to different relaxation behavior of internal stress in three composites.
TiB_(2p)/Cu composites with high reinforcement content(φ_(p)=50%,58%and 65%)for electronic packaging applications were fabricated by squeeze casting technology.The microstructures and thermo-physical properties of the TiB_(2p)/Cu composites were investigated.The results show that TiB2 particles are homogeneous and distribute uniformly,and the TiB2-Cu interfaces are clean and free-from interfacial reaction products and amorphous layers,the densifications of the TiB_(2p)/Cu composites are higher than 98.2%. The mean linear coefficients of thermal expansion at 20-100℃for TiB_(2p)/Cu composites range from 8.3×10^(-6)to 10.8×10^(-6)/K and decrease with increasing volume fraction of TiB2.The experimental coefficients of thermal expansion agree well with the predicted values based on Turner’s model.The thermal conductivities of TiB_(2p)/Cu composites range from 167.3 to 215.4 W/(m·K),decreasing with increasing volume fraction TiB2.
