Microstructural evolution during transient plastic phase processing of titanium carbide-titanium boride composites
Microstructural evolution during transient plastic phase processing of titanium carbide-titanium boride composites
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DOI：
10.1111/j.1151-2916.1996.tb08017.x
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发表时间：
1996-07
影响因子：
3.9
通讯作者：
D. Brodkin;S. Kalidindi;M. Barsoum;A. Zavaliangos
中科院分区：
文献类型：
--
作者：
D. Brodkin;S. Kalidindi;M. Barsoum;A. Zavaliangos
瞬态塑性相加工是一种在相对较低的同源温度下制备完全致密的陶瓷-陶瓷复合材料的反应热压形式。在这项研究中，这种技术已被用于两种粉末混合物-4：1 Ti/B4 C和1：1 TiC0.5/TiB 2，这是等效的元素组成方面-生产完全致密的碳化钛-硼化钛复合材料。在每种情况下形成的复合材料是由相同的最终相-TiCx，TiB 2，和Ti 3B 4，在大致相同的体积分数，但表现出明显不同的晶粒形态。对于4：1 Ti/B4 C起始组合物，Ti 3B 4相成核并作为片状物生长，但对于1：1 TiC0.5/TiB 2组合物，Ti 3B 4相作为等轴晶粒生长。TiB已被确定为“片晶”组成中的中间相，并且似乎对Ti 3B 4片晶的形成很重要。X射线衍射和扫描电子显微镜的结果表明，微观结构的演变是由硼和碳的扩散，而不是钛。此外，相对于硼，碳的更快的扩散有助于片状复合材料的微观结构演变。所制备的复合材料具有>99%的密度和良好的机械性能。片状复合材料的较高强度和韧性被认为是由于Ti 3B 4相的片状形态。
Transient plastic phase processing is a form of reactive hot pressing for fabricating fully dense ceramic-ceramic composites at relative low homologous temperatures. In this study, this technique has been used on two powder mixtures—4:1 Ti/B4C and 1:1 TiC0.5/TiB2, which are equivalent in terms of elemental compositions—to produce fully dense titanium carbide-titanium boride composites. The composites formed in each case are comprised of the same final phases—TiCx, TiB2, and Ti3B4, in roughly the same volume fractions—but exhibit distinctly different grain morphologies. Ti3B4 phase nucleates and grows as platelets for the 4:1 Ti/B4C starting composition but as equiaxed grains for the 1:1 TiC0.5/TiB2 composition. TiB has been identified as an intermediate phase in the “platelet” composition and appears to be important to the development of the Ti3B4 platelets. X-ray diffractometry and scanning electron microscopy results indicate that the evolution of the microstructure is governed by the diffusion of boron and carbon, rather than titanium. In addition, the faster diffusion of carbon, relative to boron, is instrumental in the microstructural evolution of the platelet composite. The produced composites possess >99% density and good mechanical properties. The higher strength and toughness of the platelet composite are believed to be due to the platelet morphology of the Ti3B4 phase.