Abstract
The single-crystal and polycrystalline elastic parameters of paramagnetic Fe0.6−xCr0.2Ni0.2Mx (M = Al, Co, Cu, Mo, Nb, Ti, V, and W; 0 ≤ x ≤ 0.08) alloys in the face-centered cubic (fcc) phase were derived by first-principles electronic structure calculations using the exact muffin-tin orbitals method. The disordered local magnetic moment approach was used to model the paramagnetic phase. The theoretical elastic parameters of the present Fe–Cr–Ni-based random alloys agree with the available experimental data. In general, we found that all alloying elements have a significant effect on the elastic properties of Fe–Cr–Ni alloy, and the most significant effect was found for Co. A correlation between the tetragonal shear elastic constant C′ and the structural energy difference ΔE between fcc and bcc lattices was demonstrated. For all alloys, small changes in the Poisson’s ratio were obtained. We investigated the brittle/ductile transitions formulated by the Pugh ratio. We demonstrate that Al, Cu, Mo, Nb, Ti, V, and W dopants enhance the ductility of the Fe–Cr–Ni system, while Co reduces it. The present theoretical data can be used as a starting point for modeling the mechanical properties of austenitic stainless steels at low temperatures.
Highlights
Austenitic stainless steels are paramagnetic alloys having the face-centered cubic crystallographic structure
Using the orbital method with with coherent potential approximation and PerdewPerdew-Burke-Ernzerhof generalized gradient approximation, we investigated the single-crystal
We demonstrated that all alloying elements enhanced the elastic constant C12 of the Fe–Cr–Ni system
Summary
Austenitic stainless steels are paramagnetic alloys having the face-centered cubic (fcc) crystallographic structure. They are mainly composed of Fe, a minimum of 12 atomic percentage of chromium, a minimum of 6 atomic percentage of Ni, and low amounts of carbon and nitrogen. Single-crystal and polycrystalline elastic parameters are essential in determining the mechanical properties of the materials, such as hardness, fracture, ductility, and brittleness. These parameters measure the resistance of materials to external forces, and they determine the bulk modulus B, shear modulus G, Young’s modulus E, and Poisson’s ratio ν. The principal purpose of this first-principles study is to fill this gap and to provide a comprehensive database
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