Influence of Si content on the microstructure and mechanical properties of silicon stainless steel

Effect of Silicon Content on Microstructures and Properties of Directionally Solidified Fe-B Alloy

“…In addition, the gray-white α-Fe matrix as the continuous toughening or ductile phase is distributed among the interlayer of the rod-like Fe 2 B, which reveals the formation of the dual-phase oriented microstructures of the DS Fe-B alloys. Especially, the exceeding regular laminated structure of Fe 2 B and α-Fe in DS Fe-B alloy are greatly refined and dense with the increase of Si content [ 27 ], and the forked growth phenomenon of oriented Fe 2 B intermetallic compound is reduced with the addition of Si, which infers that Si may promote the strong directional growth of Fe 2 B.…”

“…From Figure 3 a, as schematically defined with the double-headed arrow in it, the average thickness of the columnar borides d Fe2B decreases rapildly when the variation in Si content in Fe-B alloy increases from 0.00 wt.% to 2.50 wt.%, and decreases slowly after the Si content exceeds 2.50 wt.%. It can be seen that with the increase of Si content, the oriented eutectic boride becomes more thinner and smaller, which suggests that Si has a dramatically refining effect on columnar hard-phase Fe 2 B in the DS Fe-B alloy [ 27 , 28 ].…”

“…This indicates that the ferrite matrix in the as-cast DS Fe-B is gradually transformed to a solid solution of ferrite, owing to the dissolution of the small atomic radius Si into the matrix. Obviously, on one hand, Si may promote the solid solution of Cr atoms in the matrix, resulting in more (Fe-Cr) substitutional solid solutions, and on the other hand, Si is likely in favour of forming the depletion or segregation at the ferrite/boride boundaries to refine the columnar structure of the DS Fe-B alloy, which may be attribute to the constitutional supercooling effect and the outcome of Cr substitutional solid solution caused by the role of Si [ 27 , 28 , 29 ]. Actually, phase boundary segregation and matrix solution of Si may also adjust the Cr in the microstructures of Fe 2 B and α-Fe to promote the replacement of Fe atoms by Cr atoms in borides, likely forming some Cr-rich borides, as the changes of the boride peaks in XRD [ 37 ].…”

“…Pan et al, found that with the increase of Si, the content of M 2 C carbides in the microstructures of the steels decreased sharply, and the amount of M 6 C carbides increased rapidly [ 26 ]. The addition of only small quantities of Si can alter the microstructure and carbide types in steels, leading to significant enhancement in the mechanical properties of the material [ 27 ]. Bhadeshia and Cai et al studied the role of Si in silicon steel and austenitic stainless steel, which indicates that Si can promote segregation of other alloying elements, which in turn increases material strength [ 28 , 29 ].…”

“…Liu et al investigated the effect of Si on the corrosion resistance of DS Fe-B alloy in static liquid zinc, and found that Si improves the corrosion resistance to liquid zinc [ 32 ]. Prince Setia et al found that ~4 wt.% Si addition into stainless steel can give rise to phase transformation from a single-phase austennite to duplex microstructure of ferrite and austenite owing to the ferrite stabilizer effect of Si, e.g., the increase in the activity of carbon and solid solution strengthening of the Si addition [ 27 ].…”