The microstructure and corrosion resistance of SiC reinforced magnesium matrix composites with laminated gradient structure

Abstract The laminated gradient of the SiC reinforced Mg-MMCs has been report few. In this paper, the laminated gradient structure of Mg-3Al-3Sn + xSiC alloys (x = 0, 0.5, 1.0 and 2.0 wt%) were prepared via powder metallurgy and spark plasma sintering method, and the effects of different sintering rate (60 °C min, 70 °C min⁻¹ and 80 °C min⁻¹) on the phase, morphology and corrosion resistance of as-sintered and rolled-state samples with laminated gradient structure are characterized. The results shows that, from the surface to core, the grain size of samples gradually decreased with the contents of SiC addition decreasing. Compared to the as-sintered samples, the micro-hardness of rolled-state reach to 105 HV, and the electrochemical test results shows that corrosion resistance of rolled states samples prepared at 70 °C min⁻¹ increased by 88%, and the corrosion potential (Ecorr) value is −1.3162 V_SCE, which is better than other samples; the samples prepared at 60 °C min⁻¹ increased by 36%, and the samples prepared at 80 °C min⁻¹ only decreased by 5%. It provides a new method to prepare the laminated gradient structure of magnesium alloy composites.