聚碳硅烷原位自生增强钛基复合材料的组织及性能研究

以低氧氢化脱氢钛粉和陶瓷先驱体聚合物聚碳硅烷(PCS)为原料,通过粉末冶金工艺原位自生制备高强高塑钛基复合材料,探究了PCS的引入对钛基复合材料的控氧效果、烧结致密化过程、基体显微组织和力学性能的影响规律。研究表明：采用湿混包覆工艺可以将PCS包覆于Ti粉表面,有效控制材料制备过程中的氧增,其中制备的Ti-1.0 wt.% PCS复合材料的氧含量为0.21~0.24 wt.%,显著低于未经处理的CP-Ti样品(0.36~0.41 wt.%)。在烧结过程中,PCS受热分解并与Ti基体原位反应生成TiC颗粒,弥散分布在基体中,而Si元素则固溶于Ti基体。PCS的引入对Ti基体的性能具有明显的改善作用,经1200 °C/2 h烧结制备的Ti-1.0 wt.% PCS复合材料致密度达到98.4%,洛氏硬度为47.3 HRC,屈服强度为544 MPa,抗拉强度为650 MPa,延伸率为14.5%,其综合性能指标显著优于CP-Ti样品。

Microstructure and Mechanical Properties of Polycarbosilane in-situ Reinforced Titanium Matrix Composites

The increasing demand for light-weight and high-performance materials for the aerospace industry in recent years has led to the development of metal matrix composites (MMCs). As typical MMCs, titanium matrix composites (TMCs) have been regarded as potential candidates due to their high specific strength, outstanding wear resistance as well as excellent mechanical properties at high temperatures. However, it is difficult to achieve a superior titanium matrix composites with high strength and high plasticity simultaneously. In this study, the in-situ reinforced titanium matrix composites were fabricated using low-oxygen HDH Ti powders and polycarbosilane (PCS) via a powder metallurgy method, including solution-assisted wet mixing and pressureless sintering. The effects of PCS addition on the oxygen inhibition, sintering densification, microstructure and mechanical properties of the composites were investigated. Results show that the solution-assisted wet mixing process makes the Ti powders coated with PCS, which can effectively control the oxygen contamination. The oxygen content of the fabricated Ti-1.0 wt.% PCS composite is 0.21~0.24 wt.%, much lower than that of 0.36~0.41 wt.% for CP-Ti. During sintering, the pyrolysis products of PCS can react with Ti matrix to in-situ synthesized TiC particles, while Si element is dissolved in matrix. The incorporation of PCS can improve the mechanical properties of the Ti matrix. The Ti-1.0 wt.% PCS composite sintered at 1200 °C for 2 h possesses the best mechanical properties, with a relative density of 98.4%, a Rockwell hardness of 47.3 HRC, a yield strength of 544 MPa, a ultimate tensile strength of 650 MPa, and a elongation of 14.5%, which is obviously higher than CP-Ti.