T91钢服役过程中碳化物的熟化分析

通过碳化物的电解萃取、X衍射分析、能谱分析和透射电镜分析等方法,对不同服役时间的T91钢中的碳化物状态及变化进行了研究.结果表明,经长期高温高压作用后,T91钢中碳化物M23C6发生较显著的熟化.碳化物M23C6颗粒形态多由短条形变为球形,仍以板条界分布为主.同时发现碳化物M23C6的化学成分发生变化,Mo、Cr从基体中的固溶态转移到碳化物中的化合态,碳化物M23C6在T91钢中的含量显著增加,由此对碳化物熟化提出了一些新的见解.

Analysis on Ripening of Carbides during Service of T91 Steel

The morphologies of carbides and variation in T91 Steel were analyzed by electroextraction, energy spectrum, XRD, and TEM. The results show that the carbide M23C6 ripens apparently after long-term high temperature and high pressure. The morphology of some carbides M23C6 changes into globular from short plate, but the large amount of carbides are still distributed in plate. Meanwhile, the chemical constitution of M23C6 is changed as well, Mo and Cr diffuse from matrix to carbides, the content of carbides in T91 Steel increases obviously. Subsequently, a novel viewpoint about ripening of M23 C6 is proposed and the concept of Ostwald ripening is further modified.