The Effect of Precipitate Evolution on Austenite Grain Growth in RAFM Steel

Materials

Chenxi Liu¹  Jianxing Yu¹  Biyu Yan¹  Yongchang Liu¹  Huijun Li¹  Zejun Wang²  Yonghong Si² 

[1] State Key Lab of Hydraulic Engineering Simulation and Safety, School of Materials Science & Engineering, Tianjin University, Tianjin 300350, China;Tianjin Special Equipment Inspection Institute, Tianjin 300192, China;

关键词: RAFM steel;    austenite;    precipitate;    dissolution;    coarsening;   

DOI  :  10.3390/ma10091017

来源: DOAJ

【 摘 要 】

To study the effects of various types of precipitates and precipitate evolution behavior on austenite (size and phase fraction) in reduced activation ferritic/martensitic (RAFM) steel, RAFM steel was heated to various austenitizing temperatures. The microstructures of specimens were observed using optical microscopy (OM) and transmission electron microscopy (TEM). The results indicate that the M23C6 and MX precipitates gradually coarsen and dissolve into the matrix as the austenitizing temperatures increase. The M23C6 precipitates dissolve completely at 1100 °C, while the MX precipitates dissolve completely at 1200 °C. The evolution of two types of precipitate has a significant effect on the size of austenite. Based on the Zener pinning model, the effect of precipitate evolution on austenite grain size is quantified. It was found that the coarsening and dissolution of M23C6 and MX precipitates leads to a decrease in pinning pressure on grain boundaries, facilitating the rapid growth of austenite grains. The austenite phase fraction is also affected by the coarsening and dissolution of precipitates.

【 授权许可】

Unknown