Strengthening behavior in high content SiC nanowires reinforced Al composite

Recently, it has been found that the larger surface areas of SiC nanowires have significant effect on the microstructure and performance of composites. The strengthening effect of SiC nanowires is preceded to the traditional micron-scale reinforcements. However, the strengthening behavior and corresponding model of the SiCnw/6061Al composite has not been understood yet. Therefore, in the present work, SiCnw/6061Al composites with different fractions (10, 15 and 20 vol%) have been prepared by pressure infiltration method. The effect of SiC nanowires' amount on the microstructure and the mechanical properties of SiCnw/Al composites has been investigated. The interface between SiC nanowires and Al matrix was well bonded and free of interfacial reaction products regardless of heat treatments. The tensile strength of annealed SiCnw/6061Al composites was increased with the content of SiC nanowires. However, the tensile strength of aged SiCnw/6061Al composite was reached to its maximum at 15 vol%, which should be attributed to the higher porosity of the composites. The yield strength was increased with the content of SiC nanowires, and the strengthening behavior of SiCnw/6061Al composites could be described by the modified shear-lag model. The strengthening factor (the slope of σcy-Vr curves) of SiCnw/6061Al composites is much higher than that of Al composite reinforced with particulates and short whiskers.