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研究了定向凝固过程中Ti48Al7Nb2.5V1Cr合金分别与Al_2O_3、Y_2O_3、ZrO_2铸型涂层的界面反应。通过SEM、EDS以及XRD等检测方法对合金与铸型涂层的界面反应的微观组织、元素分布以及界面的相组成等进行表征;同时结合对界面的硬度测量,得到界面反应层厚度。结果表明,合金熔体与不同铸型涂层均发生了界面反应。铸型涂层材料不同,界面反应剧烈程度也不同。反应过程中在熔体和扩散元素的冲击下,物理侵蚀和化学反应同时存在形成了反应层,反应的强弱则与涂层材料有关。更值得注意的是,对钛铝合金与铸型涂层的热力学性质进行了计算。研究还表明,熔体在界面处的反应层主要由涂层材料的脱落扩散程度控制,涂层中的元素尤其是O元素的扩散是控制界面反应进程的重要因素。
The interfacial reaction of Ti48Al7Nb2.5V1Cr alloy with Al_2O_3, Y_2O_3 and ZrO_2 coatings was investigated during directional solidification. The microstructure, elemental distribution and interfacial phase composition of the interface between the alloy and the mold coating were characterized by SEM, EDS and XRD. The thickness of the interface reaction layer was also obtained by measuring the hardness of the interface. The results show that the alloy melt interfacial reaction with different mold coating. Different mold coating materials, interface reaction intensity is also different. Under the impact of melt and diffusion elements during the reaction, physical attack and chemical reaction coexist to form a reaction layer, and the reaction strength is related to the coating material. More notable is the calculation of the thermodynamic properties of the titanium-aluminum alloy and the mold coating. The study also shows that the reaction layer at the interface of the melt is mainly controlled by the degree of the coating material falling off and diffusion. The diffusion of the elements in the coating, especially the O element, is an important factor in controlling the reaction process of the interface.