Application of Grain Boundary Segregation Prediction Using a Nano-Polycrystalline Grain Boundary Model to Transition Metal Solute Elements: Prediction of Grain Boundary Segregation of Mn and Cr in bcc-Fe Polycrystals

Abstract

A prediction method for grain boundary segregation using a nano-polycrystalline grain boundary model is applied to the grain boundary segregation of Cr and Mn in bcc-Fe polycrystals for which experimental results exist, and the validity of the prediction method is verified. In this prediction method, focusing on the fact that the atomic structure of grain boundaries is almost independent of grain size, grain boundaries of polycrystals with grain sizes of the order of micrometers are modeled as grain boundaries of nano-polycrystals, for which structural relaxation calculations by molecular dynamics calculations are possible. For this grain boundary model, the grain boundary segregation energy of each site is calculated exhaustively using the interatomic potential. In addition, the average amount of grain boundary segregation in the polycrystal is calculated from the obtained grain boundary segregation energy. With this prediction method, the average amounts of grain boundary segregation and segregation energies of Cr and Mn in bcc-Fe polycrystals can be calculated and compared with the experimental results. Calculated results for both elements reproduced the experimental results well, suggesting that this prediction method is also effective in predicting the grain boundary segregation of other solute elements.

Best Papers Awarded in 2022 by <i>Materials Transactions</i>

“…4 and verified its validity. 4,30) This method was determined to accurately predict the GB segregation energy of Mn and Cr in bcc-Fe polycrystals. More than 80 different types of thermodynamically stable quasicrystals (QCs) have been identified so far.…”

“…First, it should be noted that the papers by Ito et al 4) and by Oishi et al 8) were originally published in Japanese in Journal of the Japan Institute of Metals and Materials. 30,75) They were translated to English following the rule of Materials Transactions. Comments should be added to the two papers that Dr. Kazuma Ito, the first author of the former paper, 4) is also a winner of the best paper award following from the last year.…”

“…In association with the awarded papers introduced above, popular topics that Materials Transactions published in recent years are grain boundary segregation 93) as Ito et al were concerned with, 4,30,49) creep deformation in a wide range of materials 94102) including tricrystals by Okada et al 103,104) and work hardening in various forms of deformation in an aluminum single crystal, 105) an A3104 aluminum alloy, 106) a Ti6Al4V alloy 107) and high-strength steels. 108) Furthermore, pitting corrosion resistance is also a popular issue reported by many research groups in terms of corrosion behavior of pure aluminum, 109) pure zirconium 110) and stainless steels.…”

Best Papers Awarded in 2021 by <i>Materials Transactions</i>

“…Recently, it has been shown that this prediction method can also reproduce well the grain boundary segregation of Mn and Cr in bcc-Fe polycrystals. 55,56) Fig. 4 Prediction of critical shear stresses for dislocation to pass through carbon clusters with different diameters by three types of dislocationcarbon cluster interaction mechanisms.…”