采用熔铸法制备了10％TiC／BT20复合材料，其壁厚分别为6mm、12mm和18mm。研究TiC颗粒以及基体形貌特征随壁厚的变化。结果表明TiC颗粒在基体中的分布较为均匀，初生TiC呈现出等轴或近等轴形貌，而共晶TiC为细小的棒状形态。随着壁厚的增加，TiC颗粒的尺寸随之增大，而且α集束也随之发生粗化。力学性能研究指出复合材料的抗拉强度和屈服强度随壁厚的增加而降低，归因于α集束的粗化。但是伸长率呈现出与强度变化相反的变化规律。复合材料的断裂主要受TiC颗粒的脆性断裂控制。裂纹AKTiC颗粒处形成，随后扩展到基体中，使材料失效。%A 10% TiC/BT20 composite with wall thickness of 6 mm, 12 mm and 18 mm was produced using in situ casting process. The variations of the characteristics of TiC and the matrix with wall thickness were studied. The results show that TiC particles are uniformly distributed in the matrix. Primary TiC grows in equiaxed or near-equiaxed shape, whereas eutectic TiC exhibits fine rob morphology. Particle size increases and α colonies coarse with the increase in wall thickness. Research on tensile properties shows that the ultimate tensile and yield strengths are reduced as wall thickness increases as a result of the coarsening of α colony. However, the elongation of the composite displays an opposite trend with strength. The failure of the composite is mainly controlled by the brittle fracture of TiC particles. Cracks generate at TiC particles and then spread into matrix, causing the damage of the composite.
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