稀土元素对HP40合金预氧化行为的影响

Pre-Oxidation Behavior of RE Modified HP40 Alloy

采用声发射技术原位检测稀土元素改性HP40合金经过不同氧化时间后,氧化膜在降温过程中的剥落行为。结果表明,添加稀土元素的合金经过1h预氧化后氧化膜结合强度并未得到明显提高。随着氧化时间的延长,稀土元素促进合金的内氧化,进而提高了氧化膜与基体界面结合强度。通过BSE观察发现,稀土元素促进氧化膜与基体界面内氧化产物(氧化硅)的形成。同时这种氧化硅提高了氧化膜结合强度,进而改变了氧化膜的剥落形式。

The oxide scale rupture behavior during cooling for the rare-earth modified HP40 alloy with different oxidation time was investigated by the acoustic-emission technology. The results show that the scale adherence is not improved obviously for the RE-modified alloy with 1 h pre-oxidation. However, the binding strength is increased with prolonging the oxidation time due to the internal oxidation caused by rare earth element. BSE experiment indicates the rare earth element facilitates the formation of internal oxide (silica), which changes the rupture behavior of the scale, thus improves the scale adherence.