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 (SiC_w, Si₃N_4w, Al₂O_3w) are also summarized. Finally, directions for future development of whisker-reinforced CMC are attempted to address.