IC-218合金液态轧制薄带中锆的分布

Distribution of Zr in Directly-Casting Sheet of IC-218 Alloy

鉴于Zr含量对Ni3Al基合金高温性能的重要影响,对IC218合金液态轧制薄带中Zr的分布进行了研究。结果表明,Zr在γ′和γ两相中明显偏聚于γ′;在薄带内部存在直径不到0.5μm的Ni7Zr2和ZrC颗粒,而在近表层区域存在直径可达10～30μm的ZrAl3颗粒;薄带表面出现Zr的富集,其浓度可达薄带内部的3.8倍。此外,结合液态轧制工艺的快冷条件对锆化合物颗粒及锆表面富集的可能机制进行了讨论。

In view of the importance of Zr content to the high temperature properties of Ni 3Al base alloys, the distribution of Zr in directly casting sheet of IC 218 alloy was examined. The results show that Zr remarkably segregated in phase γ ′ between phases γ ′ and γ ; the Ni 7Zr 2 and ZrC particles with diameters smaller than 0.5 μm formed inside the sheet, while ZrAl 3 grains with diameters up to 10～30 μm appeared nearby surface; and Zr segregation occurred in surface layer, at which Zr contnet is 3.8 times as high as that of the inside. The segregation mechanism of the zirconic compound and Zr during the directly casting processing was discussed.