This is the first comprehensive review on inherent anisotropic features of transition metal diboride (MB₂) and their implementation for tailoring the microstructure and properties of MB₂-based Ultra-high temperature Ceramics (UHTCs). The emphasis is on the processing approaches, microstructures, and properties of self-reinforced and/or textured MB₂-based composites with elongated MB₂ grains. The crystal structure characteristics and grain growth behaviour of MB₂ are also critically reviewed. Benefiting from the tailored microstructure, the MB₂-based ceramics exhibit some improved properties. Considering the success of Si₃N₄ ceramics in the field of structural ceramics, it is expected that the potential MB₂-based ceramic composites with abundant elongated MB₂ grains, textured structures, and controlled grain boundaries would possess improved fracture toughness, thermal shock resistance, and reliable high-temperature properties, which are desired for their practical applications. Accordingly, microstructure designing and tailoring provide an important perspective for the future development of UHTCs.

这是对过渡金属二硼化物（MB ₂）的固有各向异性特征及其用于定制基于MB ₂的超高温陶瓷（UHTC）的微观结构和性能的实现的首次全面综述。重点在于具有细长MB ₂晶粒的自增强和/或纹理化MB ₂基复合材料的加工方法，微观结构和性能。MB ₂的晶体结构特征和晶粒生长行为也得到了严格的审查。受益于定制的微结构，基于MB ₂的陶瓷表现出一些改进的性能。考虑Si ₃ N ₄的成功在结构陶瓷领域中，人们期望具有大量细长MB ₂晶粒，纹理结构和受控晶界的潜在MB ₂基陶瓷复合材料将具有改善的断裂韧性，抗热震性和可靠的高温性能，这是其实际应用所需要的。因此，微观结构的设计和定制为UHTC的未来发展提供了重要的视角。