11%Cr铁素体/马氏体钢蠕变前后的析出相研究

Precipitate phases in 11%Cr ferritic/martensitic steel before and after creep

利用透射电镜和能谱仪研究了一种11%Cr铁素体/马氏体钢在蠕变前后的析出相的类型、成分、形貌以及尺寸分布。结果表明,蠕变前钢中的析出相主要为富Cr的M（23）C6碳化物,富Nb/富Ta-Nb的MX碳化物,富Nb的MX碳氮化物。在600℃,150 MPa应力下蠕变1100 h后（未发生断裂）,M（23）C6相的化学成分和尺寸几乎没有变化,Ta-Nb富集的MC析出相溶解,Nb富集的MX析出相内Nb元素含量少量上升,Ta与Cr元素含量下降。MX相的尺寸在蠕变后明显减小。此外,在蠕变后的钢中发现了（Fe,Cr）2W型的Laves相和M6C型的碳化物。

The type,composition,morphology and size distribution of precipitate phases in an 11%Cr ferritic/martensitic steel before and after creep were investigated by using transmission electron microscope with energy-dispersive X-ray spectroscopy.The results indicate that the main precipitate phases in the steel before creep are Cr-rich M（23）C6carbide,Nb-rich/Ta-Nb-rich MX carbides,and Nb-rich MX carbonitride.After a creep test at 600℃for 1100 h under 150 MPa（without break）,the chemical composition and size of M（23）C6precipitates are almost unchanged;Ta-Nb-rich MC precipitates are dissolved;the Nb content slightly increases accompanied with decrease of Ta and Cr content in Nb-rich precipitates.The size of MX precipitates decreases obviously.In addition,（Fe,Cr）2W Laves phase and M6C carbide are observed in the steel after the creep test.