Microstructure And Corrosion Behaviors Of Fecrnibsimox Stainless Steel Fabricated By Laser Melting Deposition

In this paper, FeCrNiBSiMox (x = 1.0, 1.5, 2.0, 2.5) stainless steels were successfully prepared using a laser melting deposition technology, with the aim to investigate the effect of Mo content on microstructure and corrosion behaviors. The results showed that the as-deposited specimens were composed mostly of alpha-Fe and a small amount of (Cr, Mo)(7)C-3, and (Cr, Mo)(7)C-3 existed in the inter-dendritic (ID) region. As the Mo content increased, grain refinement could be clearly observed, and the area of the ID region increased from 27% to 54%. The low-angle boundaries accounted for 60-70% of the grain boundaries of the as-deposited specimens. Increasing the content of Mo improved the microhardness of the as-deposited specimens from 652 HV to 813 HV. The corrosion current density of the as-deposited specimens with the Mo mass fractions of 1.0%, 1.5%, 2.0%, and 2.5% were 1.37 x 10(-6), 1.02 x 10(-7), 6.19 x 10(-7), and 3.06 x 10(-7) A/cm(2), respectively. The as-deposited specimen with Mo content of 1.5% had lower cumulative erosion loss and erosion loss rate than other as-deposited specimens. The FeCrNiBSiMox (x = 1.5) specimen exhibited excellent resistance to electrochemical corrosion and cavitation erosion.