Ultrasonic-assisted hot-press sintering of Cu-Ti₃AlC₂ composites

Cu-Ti₃AlC₂ composites exhibit high mechanical strength, good electrical and thermal conductivity, low friction coefficient, and environmental adaptability via “ metal–ceramic” synergy, and are promising for applications in the field of electronic heat dissipation, power transmission, and high-temperature structural components. However, using conventional fabrication methods, Cu triggers interlayer delamination in Ti₃AlC₂ above 860 °C, whereas below this temperature, the Cu-Ti₃AlC₂ composites struggle to achieve full densification. To tackle this problem, in this study, we propose a novel ultrasonic-assisted hot-press sintering (UAHP) technique to prepare Cu-Ti₃AlC₂ composites. Using the UAHP, dense Cu-Ti₃AlC₂ composites were fabricated at 750 °C, about 100 °C lower than the conventional methods. XRD and SEM analyses revealed that Ti₃AlC₂ remained undecomposed macroscopically. TEM analysis, however, revealed that an interphase layer of approximately 150 nm, consisting of defective Ti₃AlC₂, nano-TiC, and Ti3Cu was formed. Furthermore, it was found that the dislocation distribution within Cu grains was optimized and the mechanical strength of Cu-Ti₃AlC₂ composites was enhanced, while high electrical conductivity could be preserved. Additionally, the Cu-Ti₃AlC₂ composites fabricated via UAHP exhibit excellent tribological properties. The above results demonstrate that UAHP is a potential method for achieving low-temperature densification of difficult-to-sinter materials such as Cu-Ti₃AlC₂ composites, optimizing microstructures, and elevating material performance.