Microstructure and corrosion behaviors of FeCrNiBSiMo_x stainless steel fabricated by laser melting deposition

Abstract

In this paper, FeCrNiBSiMo x (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 α-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 × 10 −6 , 1.02 × 10 −7 , 6.19 × 10 −7 , and 3.06 × 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 FeCrNiBSiMo x (x = 1.5) specimen exhibited excellent resistance to electrochemical corrosion and cavitation erosion.

Design and characterization of selective laser‐melted Ti6Al4V–5Cu alloy for dental implants

“…Therefore, from the electrochemical point of view, the number of microcells was reduced, thus improving the corrosion resistance of the specimen. [ 50 ] (c) Ti 2 Cu can produce an “envelope effect,” which can effectively prevent the contact between the titanium alloy and corrosion medium, thus protecting the surface of the titanium alloy and improving corrosion resistance. [ 51 ] Therefore, the improvement in corrosion resistance of the selective laser‐melted Ti6Al4V–5Cu alloy was directly related to 5% Cu.…”

Microstructure and corrosion behavior of FeCrNiMnMox high‐entropy alloys fabricated by the laser surface remelting

“…As indicated by the relevant research, Mo oxide could improve the resistance to attack from the aggressive ions. [ 30–32 ] It has been shown above that the addition of Mo is effective in promoting the development of Cr 2 O 3 . Therefore, the result of XPS analysis is believed to suggest that the FeCrNiMnMo 1 alloy's remelted layer is more resistant to corrosion than the FeCrNiMn alloy's remelted layer.…”

High Entropy Alloys Manufactured by Additive Manufacturing

“…Most of the additive manufactured HEAs attained a tensile strength (TS) in the range of 600-800 MPa, but with strain values that can reach 50%. [28][29][30]33,35,37,38,40,44,45,49,52,57,71,72,[74][75][76][77][78][79][80]. In the black square and also highlighted with square dots are confined most of the plain CAs.…”

“…What we can conclude from this figure is the versatility of these technologies in obtaining materials with many different balances between strength and elongation. Figure also displays selected results related to HEAs obtained by other alternative powder metallurgy routes [77,78] and a fair few high-strength AM titanium base alloys [79,80] to have the reference of some other structural competing alloys with the HEAs and also two references of other hot pressed HEAs [77,78].…”

“…This type of microstructure, in which an FCC phase coexists and is usually enriched in Fe and Cr with BCC-B2 phases enriched in Al and Ni produces severe pitting corrosion that degrades the behavior of these materials, with the B2 phases acting as an anodic agent against FCC, which acts as a cathode. The microstructural constrains that harm the corrosion behavior of HEAs are different than those that affect to the AM stainless steels, that usually are related to the formation of (Cr,Mo) 7 C 3 carbides [80]. Comparison between HEAs and stainless steels in terms of corrosion, seems to be the most appropriate, but the amount of information regarding HEAs and corrosion is much lower.…”