Novel processing strategy and challenges on whisker-reinforced ceramic matrix composites

Whisker-reinforced ceramic matrix composites (CMCs) are the emerging materials for structural applications that can work at temperature above 1500 °C, for example in next-generation gas turbines. Currently, the key issue is the choice of preparation route of whisker-reinforced CMC, as it determines whether the process can be scaled up and industrialized in the future. This review presents a composite preparation route to fabricate whisker-reinforced CMCs, i.e., sequential preparation of the whisker, whisker preform, interphase, and matrix. The composite preparation route follows the principle of near-net-size manufacturing and is highly tailorable through a rational combination of preform (gel-casting, tape-casting, additive manufacturing), interphase (chemical vapor infiltration (CVI), polymer infiltration pyrolysis (PIP), dip-coating), and matrix (CVI, PIP, reactive melt infiltration) processes. Furthermore, the main synthesis methods and morphology control mechanisms of whiskers (SiCw, Si3N4w, Al2O3w) are also summarized. Finally, directions for future development of whisker-reinforced CMC are attempted to address.