Oscillatory pressure-assisted sinter forging for preparation of high-performance SiC whisker reinforced Al₂O₃ composites

In this work, a novel process, oscillatory pressure-assisted sinter forging (OPSF), for the preparation of high-performance ceramic composites was reported. Compared with the samples made by conventional sinter forging (SF) and hot oscillatory pressing (HOP), the SiC whisker reinforced Al₂O₃ composites (SiC_w–Al₂O₃) prepared by OPSF at the same temperature exhibited a higher density and significantly improved the mechanical properties. The improvements in densification and performance are attributed to simultaneous enhanced shear deformation at both macro- and micro-scales, resulting from the combination of die-free configuration and oscillatory pressure of OPSF. And the strength of grain boundary is greatly increased when the temperature reaches 1600 ℃ of OPSF, due to that the grain-boundary sliding became pronounced at higher temperatures. The current results shed light on a powerful technique for preparing ceramic composites, which is likely applicable to other systems.