Behavior and Strengthening Mechanism of Modified SiCp in Gray Cast Iron
Several studies have shown that the mechanical properties, corrosion resistance, and wear resistance of cast alloys, such as gray iron, ductile iron, aluminum bronze, and stainless steel, can be considerably enhanced by adding modified micro and nano SiC particles (SiCp). However, the distribution of SiCp in the melt can still be improved. Investigating the morphology and interaction mechanism of these particles is insufficient. In this study, the distribution and mechanism of HT250 in melt are studied by adding different amounts of modified SiCp. Results show that the microstructure of gray cast iron can be refined, and its tensile strength can be improved by the addition of modified SiCp. The improvement increases with the increase in the amount of added SiCp. Kinetic analysis shows that the mismatch between SiC and graphite is 8.1, and the size of SiC decreases after its addition to the melt. SiC satisfies the nuclei size condition of graphite and austenite precipitation and serves as the pinning particle that hinders the movement of the grain boundary. The addition of SiC to gray cast iron is crucial in fine grain strengthening because of these behavioral characteristics.