Zhao Hongchang, Wang Zixi, Han Xi, Wang Mingjia
Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, China.
CITIC Dicastal Co., Ltd., Qinhuangdao 066011, China.
Materials (Basel). 2022 Apr 13;15(8):2847. doi: 10.3390/ma15082847.
The precipitation and growth mechanism of the Laves phase and the coarsening behaviors of Laves phase, M23C6 and MX carbonitrides have been emphatically investigated in P91 steel at 625 °C under different aging conditions. After long-term aging at 625 °C (>1500 h), it was observed that the Laves phase grew rapidly in the region near the M23C6 carbide once precipitated, and further gradually completed the engulfment process until the M23C6 carbide particles disappeared. Furthermore, a new crystallographic orientation relationship between M23C6 carbides and Laves phase has been observed at 625 °C for 5000 h, which is {0001}Laves∥{111}M23C6, <112¯1>Laves∥ <011>M23C6. The coarsening behaviors of Laves phase, M23C6 carbides and MX carbonitrides have been emphatically investigated, conforming to the existing ripening model of multicomponent alloys. The coarsening rates for the Laves phase, M23C6 and MX have values of ~32.2 (≥5000 h), 5.3 and 0.6 nm/h1/3, respectively.
着重研究了P91钢在625℃不同时效条件下Laves相的析出与长大机制以及Laves相、M23C6和MX碳氮化物的粗化行为。在625℃长期时效（>1500 h）后，观察到Laves相一旦析出就在靠近M23C6碳化物的区域迅速长大，并进一步逐渐完成吞并过程，直至M23C6碳化物颗粒消失。此外，在625℃时效5000 h时观察到M23C6碳化物与Laves相之间存在一种新的晶体取向关系，即{0001}Laves∥{111}M23C6，<112¯1>Laves∥ <011>M23C6。着重研究了Laves相、M23C6碳化物和MX碳氮化物的粗化行为，符合现有的多组元合金粗化模型。Laves相、M23C6和MX的粗化速率分别约为32.2（≥5000 h）、5.3和0.6 nm/h1/3。
