Combined Effect of TiO₂ and Metallurgical Slag Addition on the Properties of Magnesium Composites

This study investigates the effect of CaSiO₃ and TiO₂ reinforcements on the microstructure, mechanical properties, and degradation behavior of magnesium matrix composites. Using powder metallurgy, three systems were developed: Mg + CaSiO₃, Mg + TiO₂, and a hybrid system of Mg + CaSiO₃ + 5 wt.% TiO₂. Mechanical alloying, compaction, and sintering processes were applied. The hybrid system exhibited a 35% reduction in grain size, decreasing from 11.2 to 7.9 μm, resulting in a 26% increase in microhardness (95.78 HV) and a 46% increase in compressive strength (272.83 MPa) compared to pure Mg. However, degradation tests in a 3.5% NaCl solution revealed an accelerated degradation rate for the hybrid system (2804.74 mm/year), significantly higher than unreinforced Mg (207.24 mm/year). These results highlight that the combination of macro- and nano-sized reinforcements can improve mechanical performance but also leads to increased degradation, making these composites suitable for applications where controlled degradation is advantageous, such as in degradable materials for medical or energy industries.