Ru的添加对镍基单晶高温合金组织的影响

Effects of Ru Additions on the Microstructures of the Ni-based Single Crystal Superalloys

摘要:

研究了添加Ru对镍基单晶高温合金铸态、热处理及长期时效组织的影响。结果表明：添加Ru导致合金的共晶含量、一次枝晶间距降低，固溶热处理困难。添加Ru后合金的层错能显著降低，?基体中出现的扩展位错会阻碍后续位错的运动，有助于提高合金力学性能。1100℃长期时效时，添Ru加对筏化过程影响不显著，未改变TCP相的主要析出类型，但显著抑制了TCP相的析出；随时效时间的延长（如超过500 h），添加Ru对TCP相的抑制作用减弱。

Abstract:

The effects of ruthenium (Ru) additions on the microstructures of Ni-based single crystal superalloys in as-cast, post-heat treated and long term aging (at 1100 °C) are investigated by using optical microscope (OP), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that Ru additions promote the increasing of eutectic and primary dendritic arm spacing. Because Ru additions lead more refractory elements segregating (e.g. Re and W et al.) to the dendrite arm, the solution heat treatment of the 3Ru alloy is more difficult. The stacking fault energy of the g matrix is obviously decreased after Ru additions. The extend dislocations in the g matrix may impede the movement of the following dislocations during plastic deformation and improve the mechanical properties significantly. During long term aging at 1100 °C, Ru additions has no significant effects on the rafting process, and the type of topologically close-packed (TCP) phase is not changed after Ru additions (mainly P phase). However, the precipitation process of TCP phase is suppressed after Ru additions. As the aging time prolong, the suppression effects is weakening (over 500 h).