原位TiB/Ti复合材料的熔铸制备及其显微组织

结合Ti-B-Al体系的热力学及Ti-B相图,提出了可制备薄壁、复杂形状原位自生钛基复合材料构件的SMIF工艺.采用XRD、SEM和TEM等手段研究用该工艺制备的复合材料的相组成和显微组织.结果表明,钛基复合材料中生成了TiB增强相,且在基体中分布均匀,呈短纤维状;并且Al的加入使得TiB相具有较高的长径比,最高可达110.TiB增强相/基体界面清洁、无污染.受熔模精铸陶瓷型壳的激冷作用,钛基复合材料铸锭表层中TiB相垂直于铸锭的表面分布.与基体合金相比较,钛基复合材料的力学性能有了很大程度的提高.

Microstructure of investment casting in-situ TiB/Ti composites

Combined thermodynamic analysis of Ti-B-Al system with Ti-B phase diagram, the SMIF technology was developed to fabricate complex-shaped and thin-walled in-situ titanium matrix composites component. The phase compositions and microstructure of this composites were studied with XRD, SEM and TEM. The results show that TiB phases are formed in titanium matrix composite, and they are distributed uniformly in the matrix and in short-fiber shape. The addition of Al causes the higher aspect ratio up to 110 of TiB phases. And the TiB /matrix interface is clean and no contaminator. Besides, TiB phases in the surface layer tend to arrange perpendicular to the border of this composite. Mechanical properties have been improved due to the incorporation of reinforcements. The addition of aluminum element streng thens the titanium matrix alloy by solid solution strengthening. And the high aspect ratio of TiB reinforcements also improves the mechanical properties of composites.