Microstructure evolution and enhanced mechanical performance of multilayer MXene-reinforced silver matrix composites

In this study, multilayer MXenes were first incorporated into an Ag matrix through a hetero-agglomeration process followed by spark plasma sintering (SPS), with the microstructural evolution of MXenes during composite fabrication characterized using transmission electron microscopy. The partial decomposition of MXene and transformation into rutile-TiO₂ nanoparticles occurred during SPS, facilitating the generation of submicron Ag grains through effective pinning. As revealed by the Vickers hardness measurements and tensile tests, the addition of 3 vol% MXene increased the hardness and yield strength of the Ag matrix from 57.7 HV and 97.5 MPa to 116.0 HV and 129.1 MPa, representing increases of 101 % and 32 %, respectively. Quantitative calculations suggested that the improved mechanical properties of the MXene/Ag composites were primarily due to grain refinement strengthening. Meanwhile, the electrical and thermal conductivities of the 3 vol% MXene/Ag composite decreased by 9 % and 11 %, respectively. However, the ultimate tensile strength and ductility of the composites were lower than those of pure Ag, attributed to the weak MXene-Ag interfacial bonding and fracture surface observations, as well as the presence of accordion-like structures in MXene. Compared with conventional Ag matrix composites, MXene/Ag composites demonstrate a superior balance of mechanical and physical properties, making them highly suitable for applications in electrical devices. This work enhances our understanding of the interface phenomena between MXenes and metals, providing new insights for designing novel Ag matrix composites for use in conductive devices.