Effects of rare-earth micro-alloying on microstructures, carbides, and internal friction of 51CrV4 steels

Improvement of Microstructure and Mechanical Properties of Hot‐Formed Steel with Ce Addition

“…The addition of Ce to hot‐formed steel can promote the formation of substructures with high density lattice defects in the martensitic lattice, such as high density of dislocations and twins. [ 47 ] These substructures can hinder the movement of dislocations and strengthen the martensite structure.…”

“…After the addition of Ce in the experimental steel, in addition to a portion of Ce can modify nonmetallic inclusions to form Ce containing inclusions, there is also a portion of Ce can be dissolved in the steel substrate. Due to the radius of Ce atom is much larger than Fe atom, [ 47 ] the solution Ce have an affected on the lattice structure, and further lead to the change of interplanar crystal spacing. So the dark regions in Figure 10c,d are nanoscale solution Ce atomic clusters, Li et al [ 48 ] also found the same phenomenon in RE steel according their latest research.…”

Evolution of inclusions with cerium addition and effects of C-containing rare earth inclusions on the toughness of ultra-high-strength structural steel

“…However, the elongated MnS type inclusions were completely replaced by the tiny spherical Ce–S or Ce–O–S type inclusions in the L–Ce steel. These tiny spherical inclusions effectively alleviate the stress concentration around these inclusions, reduce the nucleation rate of crack sources, and hinder crack propagation during the impact test [28]. In addition, according to the previous research [29], the first-principles calculation results indicated the relatively small differences between Ce inclusions and iron matrix in terms of hardness, toughness, brittleness, and thermal expansion coefficient, which avoids the generation of large additional stress and reduces the occurrence of cracks between the inclusions and the steel matrix during the hot rolling process.…”

Study on the Occurrence State of Lanthanum in Rust Layer and Mechanism of Its Influence on Invasion State of Corrosion Atoms

“…Modification of steel with rare earth elements to improve its corrosion resistance has been widely studied. Rare earths improve the corrosion resistance of steel mainly in four ways: rare earth oxides and sulfides are generated to deoxidize and desulfurize the liquid steel, and to modify the inclusions in the steel to reduce the micro crack area between the matrix and inclusions, which reduces the starting position of pitting corrosion and improves the corrosion resistance [1][2][3] ; segregation of rare earth elements on grain boundaries is beneficial to reduce the segregation of S and P at the grain boundary, which purifies the grain boundary and improves the intergranular corrosion resistance of steel [4][5][6] ; rare earth oxide was used as nano additive to improve the corrosion resistance of steel [7] ; an appropriate amount of rare earth can effectively reduce the precipitation of harmful intermetallic compounds. [8,9] For example, precipitation phase Nb (C, N), (Nb, Ti) (C, N) can be dispersed rapidly by the dissolved rare earth element, so as to reduce the inducing source of pitting corrosion.…”