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采用普通的熔炼方法,利用钛与B4C之间的化学反应制备7715D钛基复合材料。将该复合材料热加工后得到具有网篮组织的TiC和TiB混合增强的钛基复合材料,在900～1050℃、初始应变速率为10-2～3×10$西北稀有金属材料研究院特种材料宁夏自治区重点实验室!石嘴山7530004s-1时采用材料试验仪测量该钛基复合材料的力学性能。结果表明:该复合材料的室温和高温力学性能均有提高。在1000℃、应变速率为3×10-4s-1时,所得复合材料的最大伸长率为625%,其真应力—真应变曲线呈二次硬化现象,该复合材料超塑变形性能良好。计算所得表观激活能为359～473kJ/mol;超塑变形过程中的动态再结晶是网篮钛基复合材料获得较高伸长率的重要原因;合适的应变速率能促使网篮钛基复合材料发生动态再结晶,而合适的温度则能在促进超塑变形的同时限制晶粒长大;动态再结晶和晶粒的长大使真应力—真应变曲线中出现二次硬化现象。
The common smelting method, the use of titanium and B4C chemical reaction between the preparation of 7715D titanium matrix composites. After hot-working the composite material, TiC and TiB composite reinforced titanium matrix composites with a basket structure are obtained. The initial strain rate is 10-2-3x10 at 900-1050 DEG C, and the Northwest Institute of Rare Metals Materials Key Laboratory of Ningxia Autonomous Region, Shizuishan 7530004s-1 The mechanical properties of the Ti-based composites were measured by a material tester. The results show that both the room temperature and high temperature mechanical properties of the composites increase. The maximum elongation of the composites obtained at 1000 ℃ and the strain rate of 3 × 10-4s-1 was 625%. The true stress-strain curves of the composites showed a secondary hardening phenomenon. The superplastic deformation properties of the composites were good. The calculated apparent activation energy is 359 ~ 473kJ / mol. The dynamic recrystallization in the process of superplastic deformation is an important reason for the higher elongation of the mesh-based titanium matrix composite material. Appropriate strain rate can promote the titanium matrix composite The dynamic recrystallization occurs in the material, and the proper temperature can restrain the grain growth while promoting the superplastic deformation. The dynamic recrystallization and grain growth cause the secondary stress in the true stress-true strain curve.