Fabrication, microstructures and properties of 50 vol.-% SiCp/6061Al composites via a pressureless sintering technique

Abstract

Commercial F500 SiC powder and 6061 Al powder were chosen to fabricate the 50 vol.-% SiCp/ 6061Al composites via pressureless sintering. Effects of pre-treatment of the SiC powder and sintering temperature on the microstructures and properties of the composites were studied. Densification mechanism and interfacial reaction of the composites were also investigated. The results show that the composites have a high sintering ability and a low interfacial reaction activity. The density, bending strength and thermal conductivity of the composites are all sensitive to the sintering temperature. The composites sintered at 680°C are nearly fully dense and have the following optimal properties: the relative density of 98.5%, the bending strength of 495 MPa, the TC of 153 W/(m K) and the coefficient of thermal expansion of 8.1 × 10 −6 /°C (50-100°C), which are superior to most of the SiCp/Al composites of the similar composition reported previously.

Microstructures and properties of high-fraction Sip–6061Al composites fabricated by pressureless sintering

“…the relative density, should be the key affecting factor on the mechanical properties of the composites. An analogous conclusion has also been drawn regarding the 50 vol.-% SiCp–Al alloy composites fabricated by powder metallurgy [20]. According to the Osprey research report, the bending strength decreases and the hardness increases when increasing the Si content in the high Si fraction Al–Si alloys [21], just as with the high-fraction SiCp–Al composites reported previously [22].…”

First-principles Analysis of SiC/Al Composites Interface

“…SiCp/Al composite material is a kind of material with high specific strength, large specific modulus, good thermal conductivity, good electrical conductivity, small thermal expansion coefficient, good dimensional stability, good wear resistance [1][2][3][4][5][6] etc. It has a wide range of applications in aerospace, electronic packaging, marine, automotive, precision instruments [7][8][9][10][11][12][13] etc. The properties of the composite material are mainly determined by the properties of the matrix and the reinforcement and the interface formed between the two, where in the interface plays an important role in the performance of the composite.…”