First-Principles Study on the Structural Stability and Segregation Behavior of γ-Fe/Cr2N Interface with Alloying Additives M (M = Mn, V, Ti, Mo, and Ni)

Hui Huang,Jianchun Li,Yue Li,Jie Liu,Caili Zhang,Peide Han,Xudong Fang

doi:10.3390/met6070156

Abstract

This study investigated the structural stability and electrochemical properties of alloying additives M (M = Mn, V, Ti, Mo, or Ni) at the γ-Fe(111)/Cr2N(0001) interface by the first-principles method. Results indicated that V and Ti were easily segregated at the γ-Fe(111)/Cr2N(0001) interface and enhanced interfacial adhesive strength. By contrast, Ni and Mo were difficult to segregate at the γ-Fe(111)/Cr2N(0001) interface. Moreover, the results of the work function demonstrated that alloying additives Mn reduced local electrochemical corrosion behavior of the γ-Fe(111)/Cr2N(0001) interface by cutting down Volta potential difference (VPD) between clean γ-Fe(111) and Cr2N(0001), while alloying additives V, Ti, Mo, and Ni at the γ-Fe(111)/Cr2N(0001) interface magnified VPD between clean γ-Fe(111) and Cr2N(0001), which were low-potential sites that usually serve as local attack initiation points.

Highlights

High-nitrogen austenitic steels (HNAS) are widely used in many industrial fields owing to their excellent corrosion resistance and mechanical properties
We focused on the adhesive behavior of alloying additives M (M = Mn, V, Ti, Mo, or Ni) at the γ-Fe(111)/Cr2 N(0001) interface and systematically determined the electrochemical effects of these additives at the interface using the first-principles method
On the basis of the calculated heats of segregation and work of adhesion, alloying additives V and Ti segregated at the γ-Fe(111)/Cr2 N(0001) interface and improved interfacial adhesive strength, while alloying additives

Summary

Introduction

High-nitrogen austenitic steels (HNAS) are widely used in many industrial fields owing to their excellent corrosion resistance and mechanical properties. Nitrogen dissolved in solid solution holds several beneficial effects on the mechanical properties of steels, especially related to an excellent combination of high yield strength and high fracture toughness. The excellent properties of HNAS are damaged by nitride precipitation during thermal progress such as hot forming, heat treatment, and welding, etc. Cr2 N precipitaion deteriorated the toughness, especially in the presence of cellular-type Cr2 N, and decreased corrosion resistance by forming Cr- and N- depleted regions in the vicinity of the Cr2 N [8,9,10,11]. The effect of alloy elements on the properties of steel depends on the type and characteristics.

Methods

Results

Conclusion