High content SiC nanowires reinforced Al composite with high strength and plasticity

Al matrix composites reinforced with one-dimensional nano-materials (for instance nanotubes, nanowires and nanofibres) have been widely investigated in the past decade. However, the preparation, microstructure and mechanical behavior of high content (>10 vol%) SiC nanowires reinforced Al (SiCnw/Al) has not been reported yet. In the present work, 15 vol% SiCnw/6061Al composite was prepared by the pressure infiltration method. SiCnw/6061Al composite demonstrated good machining performance since continuous chip was obtained after cut by carbide turning tools. SiC nanowires were uniformly distributed without any observance of SiC agglomerates. Long SiC nanowires were observed after etching, implying that the preparation process had shown minor damage to the SiC nanowires and therefore, the pressure infiltration method is a feasible and successful way to prepare high content SiCnw/Al composites. The interface between SiC nanowires and Al was well bonded, and no significant interfacial product was found. After aging treatment, 15 vol% SiCnw/6061Al composite demonstrated high strength (over 1000 MPa), while a comparable plasticity as Al matrix was retained. The strengthening effect of SiC nanowires could be fully utilized through the fracture of SiC nanowires. Moreover, the grain size of Al matrix in SiCnw/6061Al composite was significantly refined and polycrystalline diffraction rings were observed. Therefore, supplemented to previous results in one-dimensional nano-materials reinforced Al matrix composites, fine-grain was also found as another main strengthening mechanism.