Influence of N on precipitation behavior,associated corrosion and mechanical properties of super austenitic stainless steel S32654

Shucai Zhang¹，Huabing Li^2,1，Zhouhua Jiang^2,1，Zhixing Li¹，Jingxi Wu¹，Binbin Zhang¹，Fei Duan¹，Hao Feng¹，Hongchun Zhu¹

1. School of Metallurgy, Northeastern University2. State Key Laboratory of Rolling and Automation, Northeastern University

摘 要：The influence of N on the precipitation behavior,associated corrosion,and mechanical properties of S32654 were investigated by microstructural,electrochemical,and mechanical analyses.Increasing the N content results in several alterations:(1) grain refinement,which promotes intergranular precipitation;(2) a linear increase in the driving force for Cr2 N and Mo activity,which accelerates the precipitation of intergranular Cr2 N and π phase,respectively;(3) a linear decrease in the driving force for σ phase and Cr activity,which suppresses the formation of intragranular σ phase.The total amount of precipitates first decreased and then increased with the N content increasing.Furthermore,the intergranular corrosion susceptibility depended substantially on the total amount of precipitates and also first exhibited a decreasing and then an increasing trend as the N content increased.In addition,aging precipitation caused a considerable decrement in the ultimate tensile strength(UTS) and a remarkable increment in the yield strength(YS).Both the UTS and YS always increased with N content increasing throughout the solution and aging process.Whereas the elongation was considerably sensitive to the aging treatment,it exhibited marginal variation with the N content increasing.

关键词：