Balancing densification and MAX-phase stability in FAST/SPS Al–Ti₃SiC₂ composites

This study investigates the microstructural evolution and interfacial stability of FAST/SPS-processed Al–10 wt% Ti₃SiC₂ composites consolidated at temperatures between 500 and 600 °C. Microstructural characterization by SEM, TEM and STEM-EDS revealed progressive densification of the aluminum matrix with increasing temperature, accompanied by improved particle bonding and stable incorporation of the Ti₃SiC₂ reinforcement. The relative density increased from 92.4% at 500 °C to 99.1% at 600 °C, while hardness increased from 46 HV1 to ~ 55 HV1. TEM and STEM-EDS analyses further revealed localized interfacial features at elevated temperatures, including Ti-containing phases and local Si-rich regions near the matrix–particle interface, while the Ti₃SiC₂ reinforcement largely retained its structural integrity. Mechanical testing showed a systematic increase in compressive stress with sintering temperature, reaching ~ 525 MPa at 50% strain for the composite sintered at 600 °C. Tribological performance was strongly influenced by microstructural evolution and densification: materials processed at 500–520 °C exhibited severe adhesive-delamination wear associated with residual porosity, whereas samples sintered at 560–580 °C showed stable friction behaviour and predominantly mild abrasive wear. The results indicate that 560–580 °C represents an optimal processing window in which near-full densification is achieved while interfacial modifications remain localized, providing the most favourable combination of microstructural stability, mechanical performance and wear resistance.