K4125合金涡轮叶片榫齿荧光显示缺陷研究

通过对试车后榫齿出现荧光显示的一级工作叶片进行宏、微观分析，对缺陷打开的"断口"进行形貌观察、背散射和能谱分析，检查叶片组织，分析榫齿荧光显示缺陷性质和产生的原因。结果表明:K4125合金涡轮叶片在试车后榫齿出现荧光显示，是由于榫齿处存在富Hf氧化物夹杂，工作后沿界面张开，形成开口性裂纹；富Hf氧化物夹杂是由于合金在熔炼过程中发生了模壳反应，产生了片状HfO₂夹杂。通过控制合金中Hf的含量、熔炼过程中的真空度，加强熔炼坩埚内残留熔渣清理和加强搅拌、扒渣等手段，可有效预防此类夹杂的产生。

Analysis on Fluorescence Display Defects of Turbine Blade Tenon Tooth of K4125 Superalloy

After testing, a linear display on tenon tooth of the first stage working turbine blade was found during fluorescence detection. Macro and micro observation, BEI and EDS were carried out to analyze the "crack" and "fracture" surface. Besides, the microstructure of the blade was examined. The results show that the linear display was because there were Hf-rich oxide inclusions, leading to cracking during testing. In the process of smelting, plate HfO₂ inclusions formed due to shell mold reaction. Some measures can be taken to prevent such oxide inclusions, such as controlling the content of Hf and the vacuum degree, strengthening slag cleaning and stirring during smelting.