Secondary Precipitation Behavior of Nitride in the Electro-slag Remelted Structure of Alloy 690

• 来源期刊: 金属学报（英文版）
• 年，卷（期）: 2017,（8）
• 页码范围: 771-780
• 页数: 10页
• 语种: 英文
• DOI: 10.1007/s40195-017-0541-3

摘要

The precipitation and evolution of secondary nitrides (S-nitrides) in the Alloy 690 electro-slag remelted (ESR) structure were investigated.Experimental results indicate that S-nitrides precipitated in the interdendritic region of the ESR structure at temperatures higher than 1100 ℃.S-nitrides could spread throughout the entire interdendritic area after sufficient exposure,and they were more numerous and much finer than primary nitrides.Furthermore,after studying the evolution of S-nitride particles at 1100,1200 and 1300 ℃,it was determined that the precipitation of S-nitrides was controlled by the diffusion of nitrogen.In addition,by investigating the elemental segregation of ESR structure and calculating critical Ti concentrations,S-nitride precipitation was found to be thermodynamically inevitable in the Alloy 690 ESR structure.