高温金属材料晶体生长取向选择机理与控制

项目名称： 高温金属材料晶体生长取向选择机理与控制

项目编号： No.51331005

项目类型： 重点项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 刘林

作者单位： 西北工业大学

项目金额： 306万元

中文摘要： 本项目以先进镍基单晶高温合金及新型TiAl合金为对象，围绕定向凝固技术制备高性能航空发动机叶片过程材料晶体取向选择机理及其控制的科学问题，开展晶体生长取向选择及凝固界面各向异性研究。通过模拟和实验，阐明定向凝固温度场和溶质场对晶粒竞争生长和选晶行为的影响，获得晶体生长方向、晶体择优取向和主热流方向之间的关系以及与生长速度和温度梯度等凝固参数的影响规律，为实现三个方向一致下的晶体生长提供理论依据；揭示金属晶体择优取向与非择优取向生长的竞争机制；探明不同取向晶粒竞争生长过程及机制，确立具有最优力学性能的晶体取向生长的稳定性条件；建立在热场、晶体择优生长方向和溶质场变化条件下的晶体生长取向控制的精确模型；探明液固相变、固固相变及晶体取向的历史相关性；构建晶体取向的精确控制模型及工艺技术基础。为实现高温金属材料晶体取向的精确控制提供理论和实验依据。

中文关键词： 晶体取向;单晶高温合金;TiAl金属间化合物;定向凝固;

英文摘要： This project is targeted at advanced Ni-based single crystal superalloys and newly-developed titanium aluminide alloys, to carry out research on the selection of crystal growth orientation and solidification interface anisotropy, around the crystal orientation selection mechanism and its control during the preparation of high-performance aero-engine blades through directional solidification process. Through numerical simulation and experiments, the effect of thermal and solute fields in directional solidification on grain competitive growth and crystal selection behavior is to be clarified. The relationship among crystal growth direction, crystal preferred orientation and the main heat flow direction will be obtained as well as the influence of solidification parameters such as growth rate and temperature gradient will be investigated, in order to provide a theoretical basis for the realization consistency of those three directions during the crystal growth. The project will reveal the competitive growth mechanism between preferred orientation and non-preferred orientation in metallic materials, proved competitive growth process and mechanism for different oriented grains, establish stability conditions for the growth orientation to obtain optimal mechanical properties. We will also establish an accurate model of crystal growth orientation control under the variation of the thermal field, crystal preferential growth direction and solute field, prove the historical correlation among liquid-solid transformation, solid-solid transformation and crystal orientation, establish the precise control model of crystal orientation and technology base. The proposed project will develop theoretical and experimental basis for achieving the precise control of the crystal orientation of high-temperature metallic materials.

英文关键词： Crystal Orientation;Single Crystal Superalloy;TiAl Intermatallic Compound;Directional Solidification