新型难变形高温合金Эк151的偏析行为及均匀化工艺研究

Segregation Behavior and Investigation on Homogenization for a New Difficult-to-Deform Superalloy ЭК151 Ingot

为了解新型难变形镍基高温合金ЭК151的铸态组织特点,并为制定均匀化工艺打下理论基础,本文利用光学显微镜、扫描电镜和能谱分析研究了ЭК151合金铸锭的偏析特征;通过1100~1250℃的均匀化实验和不同温度均匀化过程的元素扩散动力学计算,研究了合金的均匀化工艺。结果表明,ЭК151合金凝固过程中,Nb、Mo、和Ti等元素在枝晶间偏析,并形成大量的γ′+γ共晶相;为保证γ′相、共晶相回溶彻底,元素扩散充分,需要在1200℃以上进行均匀化处理;针对Nb元素的扩散动力学计算结果给出了不同温度均匀化处理所需要的时间。

Segregation behavior of difficult–to-deform superalloy ЭК151 ingot was investigated by OM, SEM observation and EDS analysis. 1100~1250 ℃homogenization tests were promoted to choose the homogenization treatment. Diffusion efficiency at different temperatures was also calculated. The results show that there is a serious segregation of Nb, Mo, eds. during the solidification, which promotes γ′+γ eutectic at interdendritic. Homogenization treatment at 1200 ℃above is suggested to solute γ′ and eutectic phase. The time of homogenization was also given by kinetics calculation based on Nb- diffusion.