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Title: Electronic origin of strain effects on solute stabilities in iron

Abstract

Nonuniform strain fields might induce the segregation of alloying solutes and ultimately lead to the mechanical performance degradation of body-centered-cubic (bcc) Fe based steels serving in extreme environments, which is worthy of investigation. In this paper, two typical volume-conserving strains, shear strain (SS) and normal strain (NS), are proposed to investigate the strain effects on solute stabilities in bcc iron by first-principles calculations. For solutes in each transition metal group, the calculated substitution energy change due to SS exhibits a linear dependence on the valence d radius of the solutes, and the slope decreases in an exponential manner as a function of the absolute difference between the Watson's electronegativity of iron and the averaged value of each transition metal group. This regularity is attributed to the Pauli repulsion between the solutes and the nearest neighboring Fe ions modulated by the hybridization of valence d bands and concluded to be originated from the characteristics of valence d bonding between the transition-metal solutes and Fe ions under SS. For main-group and post transition-metal solutes, the considerable drop of substitution energy change due to NS is concluded to be originated from the low-energy side shift of the widened valence s and p bandsmore » of the solutes. Our results indicate that the stabilities of substitutional solutes in iron under volume-conserving strain directly correlate with the intrinsic properties of the alloying elements, such as the valence d radius and occupancy, having or not having valence s and p bands.« less

Authors:
; ; ;  [1];  [2];  [3]
  1. Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China)
  2. Environment and Resource System Engineering, Kyoto University, Kyoto 615-8540 (Japan)
  3. (China)
Publication Date:
OSTI Identifier:
22598869
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 7; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BCC LATTICES; BONDING; ELECTRONEGATIVITY; IRON; IRON IONS; SEGREGATION; SOLUTES; SOMMERFELD-WATSON THEORY; STABILITY; STEELS; STRAINS; VALENCE

Citation Formats

Liu, Wei, Li, Xiangyan, Xu, Yichun, E-mail: xuyichun@issp.ac.cn, E-mail: csliu@issp.ac.cn, Liu, C. S., E-mail: xuyichun@issp.ac.cn, E-mail: csliu@issp.ac.cn, Liang, Yunfeng, and Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031. Electronic origin of strain effects on solute stabilities in iron. United States: N. p., 2016. Web. doi:10.1063/1.4961318.
Liu, Wei, Li, Xiangyan, Xu, Yichun, E-mail: xuyichun@issp.ac.cn, E-mail: csliu@issp.ac.cn, Liu, C. S., E-mail: xuyichun@issp.ac.cn, E-mail: csliu@issp.ac.cn, Liang, Yunfeng, & Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031. Electronic origin of strain effects on solute stabilities in iron. United States. doi:10.1063/1.4961318.
Liu, Wei, Li, Xiangyan, Xu, Yichun, E-mail: xuyichun@issp.ac.cn, E-mail: csliu@issp.ac.cn, Liu, C. S., E-mail: xuyichun@issp.ac.cn, E-mail: csliu@issp.ac.cn, Liang, Yunfeng, and Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031. 2016. "Electronic origin of strain effects on solute stabilities in iron". United States. doi:10.1063/1.4961318.
@article{osti_22598869,
title = {Electronic origin of strain effects on solute stabilities in iron},
author = {Liu, Wei and Li, Xiangyan and Xu, Yichun, E-mail: xuyichun@issp.ac.cn, E-mail: csliu@issp.ac.cn and Liu, C. S., E-mail: xuyichun@issp.ac.cn, E-mail: csliu@issp.ac.cn and Liang, Yunfeng and Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031},
abstractNote = {Nonuniform strain fields might induce the segregation of alloying solutes and ultimately lead to the mechanical performance degradation of body-centered-cubic (bcc) Fe based steels serving in extreme environments, which is worthy of investigation. In this paper, two typical volume-conserving strains, shear strain (SS) and normal strain (NS), are proposed to investigate the strain effects on solute stabilities in bcc iron by first-principles calculations. For solutes in each transition metal group, the calculated substitution energy change due to SS exhibits a linear dependence on the valence d radius of the solutes, and the slope decreases in an exponential manner as a function of the absolute difference between the Watson's electronegativity of iron and the averaged value of each transition metal group. This regularity is attributed to the Pauli repulsion between the solutes and the nearest neighboring Fe ions modulated by the hybridization of valence d bands and concluded to be originated from the characteristics of valence d bonding between the transition-metal solutes and Fe ions under SS. For main-group and post transition-metal solutes, the considerable drop of substitution energy change due to NS is concluded to be originated from the low-energy side shift of the widened valence s and p bands of the solutes. Our results indicate that the stabilities of substitutional solutes in iron under volume-conserving strain directly correlate with the intrinsic properties of the alloying elements, such as the valence d radius and occupancy, having or not having valence s and p bands.},
doi = {10.1063/1.4961318},
journal = {Journal of Applied Physics},
number = 7,
volume = 120,
place = {United States},
year = 2016,
month = 8
}
  • In order to investigate the effects of interstitial solute atoms on very low strain-rate deformation of steel by using an interstitial free (IF) steel and an ultra-low carbon (ULC) steel, creep tests and crosshead-arresting tests were conducted at room temperature. The concentrations of solute carbon and solute nitrogen for the ULC steel were 8 and 12 ppm, respectively, and were about 20 times higher than those of the IF steel. The static tensile tests showed that the tensile properties in the two steels were quite similar. However, the room temperature creep test and the crosshead-arresting test showed that their deformationmore » behaviors were significantly different. The very low strain-rate deformation of the ULC steel was associated with the so-called dynamic strain aging, which appeared at a critical strain rate of 5.8 x 10{sup -8} s{sup -1}.« less
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