原位自生TiAl3增强Al基复合材料的组织结构及形成机理研究

采用冷喷涂技术沉积Ti-80Al（wt.%）复合涂层，通过热处理获得了原位自生TiAl3金属间化合物颗粒增强Al基复合材料涂层。采用SEM、EDS和XRD等分析了冷喷涂Ti/Al复合涂层在不同热处理温度下的组织结构演变规律及Ti、Al粒子间原位扩散反应过程，并对TiAl3金属间化合物的形成机理进行了探讨。结果表明，冷喷涂Ti/Al复合涂层组织致密，其相结构与喷涂粉末完全相同，450℃热处理后涂层局部区域发生Ti、Al间的固态扩散反应，并在Ti、Al粒子界面原位形成TiAl3金属间化合物，随着热处理温度升高，TiAl3金属间化合物的含量显著增加，600℃热处理后，Ti/Al复合涂层中的Ti粒子全部转变为TiAl3金属间化合物，获得原位自生TiAl3颗粒增强的Al基复合材料.

Study on Microstructure and Formation Mechanism of Al Matrix Composite Reinforced with In-Situ TiAl3 Intermetallic particles

The Ti-80Al (wt. %) composite was deposited by cold spraying of Ti/Al mixture powder and a Al matrix composite reinforced with in-situ TiAl3 intertermtallic particles was prepared through annealing treatment of the above-mentioned cold-sprayed Ti/Al deposit. The microstructural evolution of TiAl3/Al composite during annealing treatment were investigated by Scan electrom microscopy (SEM), Engergy disperse spectroscopy (EDS) and X-ray diffraction instrumentor. The solid diffusion reaction between Ti particles and Al particles in the annealed Ti/Al deposit was studied and the in-situ formation mechanism of TiAl3 intermetallics was investigated. Results found that the as-sprayed Ti/Al deposit exhibited dense microstucture and had the same phase constitutes with that of the feedsock powder. The solid diffusion reaction between Ti particles and Al particles occurred in the local area of Ti/Al deposit when annealed at a temperature of 450oC and consenquently formed in-situ TiAl3 intermetallics. With increasing annealing temperature, content of TiAl3 intermetallics continuously increased. After annealing at 600oC, all Ti particles in the Ti/Al deposit had completely transformed into TiAl3 intermetallics, as a result, the Al matrix composite reinforced with in-situ TiAl3 intermetallics partices was prepared.