涂层材料对钛合金机加工石墨型铸造工艺成形质量的影响

Effects of coating material on machining graphite casting processforming quality of Titanium alloy

摘要:

通过在石墨铸型内表面涂敷Y₂O₃、Al₂O₃、CaZrO₃耐火氧化物涂料,研究涂层成分对纯钛铸件界面反应和表面组织性能的影响规律。结果表明：涂敷涂料能有效克服石墨铸型对铸件的激冷作用。Y₂O₃涂料与钛液无化学反应发生,稳定性最佳,仅物理粘附于铸件表面。Al₂O₃和CaZrO₃涂料均与钛液发生了界面反应,分别生成Ti-Al-O和 Ca-Ti-O的化合物,Al₂O₃反应程度尤为剧烈。涂刷涂料后钛铸件表面晶粒尺寸、粗晶层厚度和显微硬度明显增大,变化趋势均为未涂刷< Y₂O₃< CaZrO₃< Al₂O₃。

Abstract:

The refractory oxide coating includes Y₂O₃, Al₂O₃, and CaZrO₃ were coated on the inner surface of graphite mold, to study the effect of coating composition on the interface reaction of pure titanium and its microstructure and properties. The results show that the coating can effectively overcome the chilling effect of graphite casting mould. No chemical reactions occur between Y₂O₃ and molten titanium liquid, and Y₂O₃ coating only physically adhere to the surface, so the stability of Y₂O₃ coating and titanium liquid is best. Al₂O₃ and CaZrO₃ coating have interface reaction with molten titanium liquid, and Ti-Al-O and Ca-Ti-O phase form during the interface reaction, respectively. The interface reaction between Al₂O₃ coating and molten titanium liquid is most severe. After the coating, the gain size of the surface layer, the thickness of coarse grain layer and the microhardness all increase. And these changes degree with the coating type from the small to large is Al₂O₃, CaZrO₃, Al₂O_3, respectively.