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对原位合成Ti2AlN/TiAl复合材料在原位合成及时效热处理条件下的显微组织特征进行分析,并对Ti2AlN/TiAl复合材料进行1400°C,0.5 h固溶及900°C,24 h时效热处理,研究其氮化物沉淀析出。结果表明,原位合成复合材料的显微组织由γ+α2片层团、等轴γ晶粒和Ti2AlN增强相组成。经固溶和时效处理后,获得近全片层基体结构。随着Ti2AlN含量的增加,基体近全片层结构变得不稳定。对时效后的复合材料进行TEM研究,发现在片层团晶粒边界上分布着细小的Ti2AlN沉淀相。在γ-TiAl基体内,针状Ti3AlN沉淀相以其轴向平行于基体[001]方向排列,而另一种具有较大尺寸的Ti3AlN沉淀相则在位错处沉淀析出。
The microstructure of Ti2AlN / TiAl composites synthesized in-situ and aging heat treatment were analyzed. The Ti2AlN / TiAl composites were solution treated at 1400 ° C for 0.5 h and aged at 900 ° C for 24 h Heat treatment to study its precipitation of nitrides. The results show that the microstructure of in - situ composites consists of γ + α2 lamellae, equiaxed γ grains and Ti2AlN reinforcing phase. After solution treatment and aging treatment, the nearly whole sheet was obtained. With the increase of Ti2AlN content, the structure of the near-all-platelet in the matrix becomes unstable. The TEM study of the composites after aging shows that the fine Ti2AlN precipitates are distributed on the grain boundaries of the lamellae. In the γ-TiAl matrix, the needle-like Ti3AlN precipitates are arranged axially parallel to the [001] direction of the matrix, whereas the precipitates of Ti3AlN, which has a larger size, are precipitated at the dislocations.