蠕变过程中P91钢晶界析出相的变化行为  

Behavior of grain boundary precipitates of P91 steel during creep process

作　　者：顾宝兰[1] 刘嘉晨 孙浩宇 柳旺 于海洋[1] Gu Baolan;Liu Jiachen;Sun Haoyu;Liu Wang;Yu Haiyang(China Special Equipment Inspection and Research Institute,Beijing 100029,China)

机构地区：[1]中国特种设备检测研究院,北京100029

出　　处：《金属热处理》2023年第5期25-31,共7页Heat Treatment of Metals

基　　金：“十四五”国家重点研发计划(2021YFC3001801);国家市场监督管理总局科技计划(2017QK101)。

摘　　要：对600℃和650℃蠕变持久断裂试验过程中P91钢组织演变及晶界析出相的变化规律进行了研究。结果表明,在蠕变过程中,P91钢马氏体板条组织随蠕变断裂时间增加逐渐趋于分散,晶界析出相的数量及尺寸增加。晶界上的析出相主要为M_(23)C_(6)相和Laves(Fe2Mo)相,Laves相的形核点主要位于晶界上M_(23)C_(6)相界面处,晶界上的M_(23)C_(6)相与基体相比具有更高含量的Mo,为Laves相的形成和粗化提供了有利条件,同时晶界上偏聚的Si增加了钢的自扩散系数,促进了Laves相的形成,也使得Laves相的粗化速率较M_(23)C_(6)相更高。在蠕变过程中P91钢的硬度随断裂时间的延长呈下降趋势,且试验温度越高硬度下降越明显。Microstructure evolution and change law of grain boundary precipitates of P91 steel during the 600℃and 650℃creep rupture tests were studied.The results show that during the creep process,martensite lath tends to disperse gradually with the increase of creep rupture time,and the number and size of grain boundary precipitates increase.The grain boundary precipitates are mainly M_(23)C_(6)and Laves(Fe2Mo)phases,the nucleating location of Laves phase is mainly at the interface of M_(23)C_(6)phase on the grain boundary,because M_(23)C_(6)phase on grain boundary has a higher content of Mo than that in the matrix,providing favorable conditions for the formation and coarsening of Laves phase.At the same time,the segregation of Si on grain boundary increases the self diffusion coefficient of the steel,promotes the formation of Laves phase,and also makes the coarsening rate of Laves phase higher than that of M_(23)C_(6)phase.During the creep process,the hardness of the P91 steel decreases with the extension of creep rupture time,and the higher the test temperature,the more obvious the decrease of the hardness.

关 键 词：P91钢 蠕变持久 LAVES相 晶界析出相 

分 类 号：TG142.1[一般工业技术—材料科学与工程]