Microstructure, mechanical properties and wear behavior of Mg matrix composites reinforced with Ti and nano SiC particles

Abstract

This study examines the mechanical properties and wear mechanisms of magnesium (Mg) metal matrix composites reinforced with titanium (Ti) and silicon carbide (SiC) particles. Three different composite formulations were investigated: Mg-30 wt% Ti (A), Mg-25 wt% Ti-5 wt.% SiC (NB), Mg-20 wt% Ti-10 wt% SiC (NC), and Mg-15 wt% Ti-15 wt% SiC (ND). These composites were fabricated through ball milling and spark plasma sintering (SPS). The incorporation of SiC particles significantly enhanced grain refinement and phase formation within the composites. Density analysis revealed that the actual densities of the composites were lower than the theoretical values, with Composite A exhibiting the highest actual density of 2.15 g/cm³ and the lowest porosity of 16.31%. The introduction of SiC particles increased porosity, with Composite NB displaying the highest porosity at 30.58%. Hardness testing indicated that Composite NC, containing 10 wt% SiC, achieved the highest hardness of 137 HV. In contrast, Composite ND, with 15 wt% SiC, showed a reduced hardness of 115 HV, attributed to increased porosity and potential SiC particle agglomeration. Wear behavior was evaluated using a pin-on-disc tribometer. Weight loss measurements indicated that Composite A had the lowest weight loss (1.1–2.1 mg), while Composite NB experienced the highest weight loss (2.8–8.3 mg) due to increased porosity. Composite NC demonstrated a balance with moderate weight loss (2.0–3.8 mg). The coefficient of friction (COF) varied with SiC content and applied loads (2, 4, and 8 N), with Composite A demonstrating the lowest COF values (2.3–2.8) and stable performance across different loads. Composite NB exhibited higher COF values (3.5–4) and significant fluctuations due to elevated porosity and the presence of SiC particles. Composite NC showed better wear resistance and more stable COF values (2.5–2.9) compared to NB and ND.