网状结构TiBw/Ti60复合材料的高温塑性变形与强化和氧化机理

以TiB2颗粒和Ti60耐热钛合金颗粒为原料，以TiB2颗粒与基体Ti发生化学反应生成TiB晶须增强相为原理，以具有自主知识产权的低能球磨和真空反应热压烧结技术为方法，制备TiB晶须呈网状分布的Ti60高温钛合金基复合材料。采用高温压缩变形方法研究复合材料在不同变形温度和应变速率下的应力-应变特性与组织性能演化规律，提出本构方程和热加工图，揭示变形机制。研究热挤压和热轧制变形对复合材料组织性能的影响规律和机制，优化热成形工艺参数。研究热处理对复合材料组织与性能影响规律，优化热处理工艺参数。测试复合材料的高温拉伸、高温蠕变和高温抗氧化性能，揭示高温强化与高温氧化机理，阐明网状分布的TiB晶须在复合材料高温特性中的作用机制。该复合材料的耐热性接近TiAl金属间化合物，同时有良好的塑性成形能力。本项目将为航天航空对可在700-800℃使用的轻质、高强、耐热结构材料的需求提供理论支撑和技术保障。

Using TiB2 particle and Ti60 alloy particle as the starting materials, TiB whisker reinforced Ti60 alloy composite with a network reinforcement distribution is fabricated by low-energy milling and vacuum reaction hot sintering techniques. The TiB whisker reinforcement is formed by the reaction between TiB2 particle and Ti matrix during hot sintering. Stress-strain behavior and evolution of microstructure and properties of the composite are investigated by hot compression test with different temperature and strain rate, meanwhile, the constitutive equation, processing map and deformation mechanism are obtained. Effects of hot extrusion and hot rolling on microstructure and properties of the composite are researched, and the deformation parameters are optimized. Effects of heat treatment on microstructure and properties of the composite are studied, and the heat treatment parameters are optimized. High temperature tensile property, high temperature creep property and high temperature oxidation properties are tested, and the high temperature strengthening and oxidation mechanisms of the composite are pointed out. Function of the network distributing TiB whisker in the high temperature characteristic of the composite is analyzed. The composite has a similar high temperature properties and higher plastic forming ability compare to the TiAl intermetallic compound. This project will provide theoretical and technical basis for the applications of low-density, high-strength and high thermal resistance alloys using at 700-800℃ in aerospace industry.