Elastic Properties of FeCr20Ni8Xn (X = Mo, Nb, Ta, Ti, V, W and Zr) Austenitic Stainless Steels: A First Principles Study

Yuchen Dou,Hong Luo,Jing Zhang

doi:10.3390/met9020145

Yuchen Dou, Hong Luo + Show 1 more

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https://doi.org/10.3390/met9020145

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Abstract

Austenitic stainless steels suffer from intergranular corrosion and stress corrosion cracking when exposed to elevated temperature (500–800 °C). Under these environments, Cr-carbides and Cr-carbontrides precipitate at the grain boundaries, which results in the formation of Cr-depleted zone. In practice, alloying elements could be added into austenitic stainless steels to modify the precipitation processes. Besides the precipitation processes, the elastic properties of the iron matrix would be influenced. Using the exact muffin-tin orbitals (EMTO) method, the solute effects on the elastic properties of FeCr20Ni8 austenitic stainless steels were studied. Based on the simulated shear modulus (G) and bulk modulus (B), we proposed a design map for FeCr20Ni8 based alloys, aiming to provide a basis for the design of high-performance austenitic stainless steels.

Highlights

Austenitic stainless steels are widely used in the nuclear, oil and chemical industries, owing to their excellent mechanical properties, weldability and corrosion-resistance properties [1,2,3,4]
We performed first principle simulations based on the exact muffin-tin orbitals (EMTO) method [19,20]
In the full charge density technique (FCD) calculation, the exchange–correlation interactions were described by the generalized gradient approximation (GGA) in the Perdew–Burke–Ernzerhof (PBE) form [26]

Summary

Introduction

Austenitic stainless steels are widely used in the nuclear, oil and chemical industries, owing to their excellent mechanical properties, weldability and corrosion-resistance properties [1,2,3,4]. When exposed to elevated temperature (500–800 ◦ C), these alloys become susceptible to intergranular corrosion and stress-corrosion cracking. Under these environments, Cr-carbides and Cr-carbontrides precipitate at the grain boundaries, which results in the formation of the Cr-depleted zone [5,6,7]. C, aiming to suppress the Cr-carbides and Cr-carbontrides and avoid the formation of Cr-depleted zone [3,8,9] It should be noted the addition of carbide-forming elements influences the precipitation processes, and changes the elastic properties of the iron matrix. These authors revealed a very interesting trend that relatively high values of G correspond to relatively low values of B, and vice versa

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