Wang Xicheng, Zheng Yunfei, Han Shiwei, Xiao Shulong, Tian Jing, Xu Lijuan
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China.
School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
Materials (Basel). 2024 Dec 30;18(1):110. doi: 10.3390/ma18010110.
In this study, a (TiB + TiC + YO)/α-Ti composite was prepared by induction skull melting to investigate its creep behavior and microstructure evolution under different temperatures and stresses. The results show that the microstructure of the composite in the as-cast state is a basket-weave structure, and the main phase composition is α lamella, containing a small amount of β phase and equiaxed α phase. The creep life of the composite decreases significantly when the temperature is increased from 650 °C to 700 °C, and the steady-state creep rate is increased by 1 to 2 orders of magnitude. The creep stress exponent at 650 °C and 700 °C is 2.92 and 2.96, respectively, and the creep mechanism of the titanium matrix composite is dominated by dislocation movement. TiB and TiC exhibit synergistic strengthening effects, and YO remains stable during creep. The reinforcements strengthen the composite by impeding the dislocation movement. The accelerated dissolution of β phase is one of the major reasons for the decrease of creep properties of composite with increasing temperature and stress. Silicide precipitation was observed near the reinforcements and dissolved β-Ti, mainly in elliptical or short rod shapes, which pins dislocations and improves the creep performance of the composite. The results of this study can provide theoretical guidance and practical reference for the subsequent development and application of hybrid reinforced titanium matrix composites.
在本研究中，通过感应 skull 熔炼制备了一种 (TiB + TiC + YO)/α-Ti 复合材料，以研究其在不同温度和应力下的蠕变行为及微观结构演变。结果表明，铸态复合材料的微观结构为篮状编织结构，主要相组成为α薄片，含有少量β相和等轴α相。当温度从650℃升高到700℃时，复合材料的蠕变寿命显著降低，稳态蠕变率提高1至2个数量级。650℃和700℃时的蠕变应力指数分别为2.92和2.96，钛基复合材料的蠕变机制以位错运动为主导。TiB和TiC表现出协同强化作用，且YO在蠕变过程中保持稳定。增强相通过阻碍位错运动来强化复合材料。β相的加速溶解是复合材料蠕变性能随温度和应力升高而降低的主要原因之一。在增强相和溶解的β-Ti附近观察到硅化物沉淀，主要呈椭圆形或短棒状，其钉扎位错并改善了复合材料的蠕变性能。本研究结果可为后续混杂增强钛基复合材料的开发与应用提供理论指导和实际参考。
