Fabrication and properties of Fe matrix composites reinforced by macro-particles

The basic challenges in the preparation and application of particle-reinforced metal matrix composites are the difficulty in achieving a uniform and stable mixing and the weak bonds between the particles and matrix. At present, these challenges are mainly tackled by making the particles into precursor beforehand and adopting the wetting treatment technologies, respectively. However, these measures can result in lower production efficiency and higher preparation costs. Based on the molten metal die forging process, an innovation technology termed "mixing by the molten metal and cohering by high pressures" was proposed to prepare the metal matrix composites reinforced with ceramic particles without a precursor or wetting them beforehand. Using this technique, a kind of ZTA particles-reinforced KmTBCr26 cast iron wear resistant composite with a good compound effect had been prepared, and the microstructure, hardness, and impact property of the ZTA/KmTBCr26 composite was studied. The study reveals that the particle distribution in the ZTA/KmTBCr26 composite is generally uniform, and the interfacial bonding between ceramic particle and KmTBCr26 matrix is of micromechanical interlocking. The results of impact tests show that the impact toughness of the composites is significantly lower than that of the single metal, and the fracture morphology indicates that the fracture of the composites extends through the ceramic particle instead of the matrix. No particle detachment is observed, which indicates a high bonding strength between the particles and matrix. Furthermore, the dry friction and wear properties of the ZTA/KmTBCr26 composite and KmTBCr26 cast iron were investigated. The results show that the wear resistance of the composite is 1.82 times that of the KmTBCr26 cast iron when the load is lower, while the wear resistance of the composite increased by 3.3 times under the higher load.