硼含量对IC10高温合金凝固行为的影响

Effect of Boron Content on Solidification Behavior of IC10 Superalloy

采用差示扫描量热(DSC)、等温淬火和显微组织分析方法对比分析含硼量为0.005%(质量分数,下同)和0.03%的IC10合金显微组织及组成相的形成过程,研究不同硼含量合金中初生相的析出温度及析出顺序。结果表明:DSC的冷却曲线上可显示出γ、MC碳化物、(γ+γ′)共晶以及次生γ′的析出峰,但微量相M3B2硼化物和Ni5Hf相未能显示。等温淬火法可以确定所有相的析出温度。不同含硼量合金的相组成相同,按形成先后顺序六种相分别为γ、MC、(γ+γ′)共晶、次生γ′、M3B2和Ni5Hf。IC10合金含硼量的增加,显著提高了M3B2和(γ+γ′)共晶的含量(体积分数),使合金液相线和固相线温度降低,同时延缓了MC碳化物和(γ+γ′)共晶的形成。

The as-cast microstructure and formation process of phases for IC10 superalloy containing 0. 005% （mass fraction） and 0.03% boron were comparatively analyzed by differential scanning calo- rimetry （DSC）, isothermal quenching and microstructural analysis methods. Precipitation tempera- tures and sequence of initial phases in two IC10 alloys with different B content were researched. The results show that the exothermal peaks of formation for γ, MC carbide, （γ-γ＇） eutectic and seconda- ry γ＇ phase reveal on DSC cooling curves, but the corresponding peaks of the minor M3B2boride and Ni5Hf phase do not appear. However, the precipitation temperature of all phases can determine by isothermal quenching method. The alloys with different content of boron have same phase component and the formation sequence of six phases is γ, MC, （γ-γ＇） eutectic, secondary γ＇, M3B2 and Ni5 Hf in turn. The increase of boron content enhances the volume fraction of M3B2 and （γ-γ＇） eutectic, de- creases the temperature of liquids and solidus and also delays the formation of MC and （γ-γ＇） eutec- tic obviously.