NiAl-Cr(Mo)共晶合金微观组织的热稳定性研究

项目名称： NiAl-Cr(Mo)共晶合金微观组织的热稳定性研究

项目编号： No.51501147

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 王雷

作者单位： 西安理工大学

项目金额： 20万元

中文摘要： NiAl-Cr(Mo)共晶合金因熔点高、密度低、导热性好和优异的抗氧化性能等优点具有广阔的应用前景，但是其组织(层片组织和层片内纳米级颗粒)的热稳定性较差，限制了其作为航空发动机热端部件材料的应用。研究发现层片组织的热稳定性主要与层片间距和固溶元素有关，对于层片内椭球状纳米级颗粒的热稳定性，讨论其熟化规律更为重要。本申请项目拟采用定向凝固技术对层片间距进行控制，研究层片间距与层片组织热稳定性的关系，明确作为高温下层片组织稳定依据的临界间距；针对固溶元素，需探明Fe和Co分别对层片组织热稳定性的作用规律，并揭示层片组织不稳定机制；采用TEM观察椭球状颗粒在尺寸和形貌上的变化，通过测量不同时间段内的颗粒尺寸来总结其熟化规律，并揭示其粗化机制。在此基础上，探索该共晶合金组织的热稳定性与高温强度的关系，为实现优异的高温性能提供实验依据和理论支持。

中文关键词： NiAl-Cr(Mo)共晶合金；微观组织的热稳定性；定向凝固

英文摘要： NiAl-Cr(Mo) eutectic alloy possesses a vast application prospect due to some advantages, such as high melting temperature, relatively low density, good thermal conductivity and excellent oxidation resistance. However, the poorly thermal stability of lamellar structure and nanoscale particles in lamellar structure restricts the application of serving as the aeroengine hot end components. The research shows that the lamellar spacing and the solid solution element have an effect on the thermal stability, and the investigation of ripened rule of axioliticly nanoscale particles in lamellar structure is important for the thermal stability of axiolitic particle. We can control the lamellar spacing by directional solidification in this project and then clarify the effect of lamellar spacing on the thermal stability of lamellar structure to obtain a critical lamellar spacing in which there is a transition from unstable lamella to stable lamella. For the solid solution element, it is necessary to ascertain the effect of Fe and Co on the thermal stability of lamellar structure and reveal the unstable mechanism of lamellar structure. Furthermore, the morphology of axioliticly nanoscale particles is observed by TEM, and then the ripened rule of particles is concluded by the measurement of particle size at different time, and the coarsening mechanism of particles is revealed. Based on the preliminary work, the relation between the thermal stability of NiAl-Cr(Mo) eutectic structure and elevated temperature strength is investigated to provide the experimental basis and theoretical support for obtaining an excellent elevated temperature property.

英文关键词： NiAl-Cr(Mo) eutectic alloy;Thermal stability of microstructure;Directional solidification