Effect of Rare Earth La on Microstructure and Properties of 0.15 nanoSiC p /Zn-36.5Al-2.5Cu-0.8 Mg Composites

The effects of La content on the microstructure and properties of 0.15nanoSiC p /Zn-36.5Al-2.5Cu-0.8 Mg composites were studied. Results show that La not only effectively eliminated the shrinkage defects during the solidification process, but also refined the as-cast microstructure and promoted the dispersion of nano-reinforced particles. The improvement in mechanical properties of the composites gradually slowed down with the addition of La, but the wear resistance significantly increased with the increased La content. Thermal mismatch strengthening mechanism was identified in nano-SiC p on Zn-36.5Al-2.5Cu-0.8 Mg matrix induced by La addition. In addition, the rare earth compounds formed by excessive La were easy to aggregate on the grain or grain boundary, which resulted in brittle fracture.