论文部分内容阅读
本文研究了镧在钴基超合金GH188中的作用及其分配。镧在基体及M_6C相中的分配大约为9:1,大部分镧偏聚在晶界处。在该合金中镧化物主要是La_2O_3和La_2O_2S;用X射线和扫描电镜发现.该合金在空气中于900～1200℃经0～100h的氧化特性遵循一般的抛物线氧化规律,添加镧可提高氧化激活能值,其氧化皮主要由(Co、Ni)Cr_2O_4和一定量的Cr_2O_3及βCo组成,而铬离子在Cr_2O_3中的扩散是控制氧化速率的因素。镧能显著改善该合金氧化皮的致密性、连续性、稳定性和粘附力,并能提高其持久强度和持久塑性。
In this paper, the role of lanthanum in cobalt-based superalloy GH188 and its distribution were studied. The distribution of lanthanum in the matrix and M_6C phase is about 9: 1, most of the lanthanum segregates at the grain boundaries. The lanthanides in this alloy are mainly La 2 O 3 and La 2 O 2 S. X-ray diffraction and scanning electron microscopy showed that the oxidation behavior of the alloy at 900-1200 ℃ for 0-100h followed the general parabolic oxidation law. Adding lanthanum could increase the activation of oxidation The oxide scale is mainly composed of (Co, Ni) Cr 2 O 4 and a certain amount of Cr 2 O 3 and βCo. The diffusion of chromium ions in Cr 2 O 3 is the factor that controls the oxidation rate. Lanthanum significantly improves the compactness, continuity, stability and adhesion of the oxide scale of the alloy, as well as its long-term strength and long-term plasticity.