The influence of particle types of metal reinforcement on the microstructure and properties of magnesium-based composites

Magnesium-based composites reinforced with metallic particles are highly valued for their enhanced modulus and balanced strength-ductility. This study systematically investigates the effects of three typical metallic particles (Ti, Fe, Ni) on the microstructure, mechanical properties, and corrosion performance of GWZ1021 (Mg-10Gd-1.7Y-1Zn-0.5Zr-1Ca) alloy composites prepared by stir casting and hot extrusion. Microstructural characterizations via SEM, EDS, EBSD, and XRD reveal that all three particles refine the grain size of both as-cast and as-extruded specimens, weaken the extrusion texture, and alter the morphology of the LPSO phase (layered for Ti, block-like for Fe, and lamellar for Ni). Mechanical property tests show that Ti particles yield the most significant strengthening effect: the extruded Ti P /GWZ1021 composite exhibits a 31.3% increase in yield strength (to 398 MPa) and an 18.2% improvement in plasticity (to 14.3%), followed by Fe P /GWZ1021 (6.6% strength increase, 16.5% plasticity increase), while Ni P /GWZ1021 shows a modest 5.0% strength gain with nearly unchanged plasticity. The strengthening mechanisms of composites with Ti particles mainly benefits from uniform dispersion of second phase, and excellent interface bonding. Corrosion tests (hydrogen evolution, weight loss, and electrochemical measurements) indicate that Ti P /GWZ1021 composite shows similar corrosion resistance (corrosion current density reduced to 7.22×10 -5 A/cm 2 ) to that of GWZ1021 alloy, whereas Fe and Ni particles drastically accelerate corrosion (corrosion current densities increased to 8.13×10 -3 and 22.39×10 -3 A/cm 2 , respectively). This discrepancy arises from the formation of a dense TiO 2 protective layer on Ti particles, while Fe and Ni particles act as efficient cathodic sites for galvanic corrosion due to their large potential difference with Mg and high catalytic activity for hydrogen evolution. In summary, Ti P /GWZ1021 composites achieve the optimal balance of strength, ductility, and corrosion resistance, making Ti particles a promising reinforcement for high-performance magnesium-based composites.