Abstract
Aiming at serious catastrophic oxidation problem of super-austenitic stainless steel S32654,the influence of different rare earth elements on its oxidation behavior was comparatively investigated at 1200℃.The mechanism of Y significantly improving high-temperature oxidation resistance of S32654 was unveiled.The results demonstrated that Y played much better beneficial roles than Ce and La in the initial forma-tion of oxide layer:(1)Y promoted Cr segregation to steel surface to combine with O;(2)its preferential oxidation provided nucleation cores for Cr2O3.Both roles jointly promoted the selective oxidation of Cr and then the formation of protective Cr-rich oxide layer.This provided good prerequisites for inhibiting the formation and volatilization of MoO3.Additionally,Y cation segregation to oxide grain boundaries fur-ther promoted the selective oxidation of Cr and Si to form more protective oxide layer.These beneficial roles of Y essentially eliminated the synergistic effects of MoO3 volatilization and lamellar Cr2N precipi-tation on catastrophic oxidation.Accordingly,the oxidation resistance of Y-bearing S32654 was improved by 22％-45％.
基金项目
国家自然科学基金(U1860204)
国家自然科学基金(52004061)
Talent Project of Revitalizing Liaoning(XLYC1802101)
中国博士后科学基金(2020M670777)
Northeastern University Postdoctoral Funds(20200321)
Fundamental Research Funds for the Cen-tral Universities(N2125017)
NETL
NSTL
维普
万方数据