针对(TiB+La2O3)/IMI834颗粒增强钛基复合材料开展了900~980 ℃、0.0003~0.03 s-1条件下的超塑拉伸试验,研究了该复合材料的超塑性变形行为及微观组织演变规律。结果表明,随着变形温度升高,材料流动应力降低,断后伸长率呈先增后降的趋势;降低应变速率,流动应力减小,伸长率表现为先增大后减小的特征,且变形温度越低,峰值应力对应变速率的波动越敏感;在940 ℃、0.003 s-1条件下,复合材料获得最大伸长率为564%;应变速率敏感性指数m均大于0.3,900~960 ℃时应力指数n介于2~3之间,980 ℃时n>3,超塑变形激活能Q的平均值约为383 kJ/mol,表明900~960 ℃时复合材料超塑变形以晶界滑动和位错滑移协调为主,而在980 ℃时转变为位错滑移主导,超塑性能下降;钛基复合材料在变形初期晶粒细小,硅化物均匀分布,仅在TiB增强体两端因变形不协调产生孔洞;随着变形量增加,动态再结晶晶粒不断长大,基体内部逐步萌生孔洞,变形后期孔洞持续聚集连通,最终引发材料断裂失效。Superplastic tensile tests were conducted on (TiB+La2O3)/IMI834 particulate-reinforced titanium matrix composites at temperatures of 900–980 ℃ and strain rates of 0.0003–0.03 s‒1. The superplastic deformation behavior and microstructural evolution of the composite were investigated. The results indicate that increasing deformation temperature reduces the flow stress, while the elongation to failure rises first and then declines. Reducing the strain rate leads to decreased flow stress, whereas the elongation first increases and subsequently decreases. The peak stress is more sensitive to variations in strain rate at lower deformation temperatures. A maximum elongation of 564% is achieved for the composite at 940 ℃ and 0.003 s‒1. The strain rate sensitivity index m is higher than 0.3. The stress exponent n ranges from 2 to 3 within 900–960 ℃, and exceeds 3 at 980 ℃. The average activation energy Q for superplastic deformation is approximately 383 kJ/mol. These results reveal that the superplastic deformation is dominated by coordinated grain boundary sliding and dislocation slip at 900–960 ℃, whereas dislocation slip becomes the dominant mechanism at 980 ℃, resulting in degraded superplasticity. At the early deformation stage, the titanium matrix composite possesses fine grains with uniformly distributed silicides, and cavities only initiate at both ends of TiB reinforcements due to deformation incompatibility. As deformation proceeds, dynamically recrystallized grains continuously grow, and cavities gradually nucleate within the matrix. In the late deformation stage, cavities continuously aggregate and coalesce, eventually causing fracture failure of the material.