TiAl基合金熔炼用多元钙钛矿结构氧化物耐火材料基础研究

因具有低密度和高强度等优异性能，TiAl基合金作为新一代高温合金已受到广泛关注。而TiAl基合金在熔炼时易出现夹杂和偏析等现象，采用坩埚感应熔炼能有效解决此问题，并能克服常用强制水冷熔炼所带来的低效率和高能耗等不足。但坩埚感应熔炼因坩埚耐火材料与TiAl基合金熔体界面反应会污染合金的问题，导致其应用存在很大挑战。这个问题的改善与耐火材料稳定性及微结构和合金熔炼温度及时间密切相关。本项目拟从Ca2+掺杂BaZrO3耐火材料固相合成制备及微结构调控，耐火材料对TiAl基合金熔体稳定性和合金熔炼温度及时间协同作用开展研究，阐明耐火材料固相合成路径及机制，揭示Ca2+掺杂对BaZrO3耐火材料在TiAl基合金熔体中稳定性改善机理，厘清耐火材料微结构（晶粒尺寸和孔隙率）与熔炼参数（温度和时间）对合金氧含量控制的关联规律；突破TiAl基合金坩埚感应熔炼关键工艺技术，为其在工程化应用奠定理论和实践基础。

TiAl-based alloys, due to the low density and excellent specific strength, has been attracted attentions as the new generation superalloy. However, the inclusions and segregation are always appeared in the alloys in the process of melting. Induction melting of the alloys with the refractory crucible is an effective way for solving this problem, and overcoming the low efficiency and high energy consumption caused by forced water cooling. The interaction between the alloy melt and the crucible refractory can cause the melt contamination, which leads to the challenges for the application of the alloys. Also, the alloy melt contamination could be decreased by improving the stability of the crucible refractory and controlling the melting temperature and time, respectively. In this project, the process of solid-phase synthesis and the evolution of microstructure Ca2+ doped BaZrO3 refractory will be studied as well as the melting temperature and time for induction melting of alloys. The path and mechanism of solid- phase synthesis is clarified. The effect of Ca2+ content on the stability of BaZrO3 refractory was investigated, and the relationship between the microstructure (grain size and porosity) of the refractory crucible and the melting parameters (temperature and time) in controlling the oxygen content of alloys is presented. The key problem of induction melting of TiAl-based alloys can achieve breakthroughs, and it lays a theoretical and practical foundation for its application in engineering.