Abstract
In this work, we conducted a high-throughput atomistic simulation of the interstitial solid solutions of hydrogen in α-Fe. The elastic constants and moduli were calculated. Through statistical analysis of structures and results, the influences of the microscopic distribution of hydrogen on the elastic moduli, as well as hydrogen-induced hardening and softening, are discussed. We found that even though the uniformly distributed hydrogen caused slight softening in α-Fe, the distribution of hydrogen at different adjacent positions significantly affected the elastic moduli. For example, hydrogen increased the Young’s modulus and shear modulus at the 5th and 10th nearest neighbors, resulting in hardening, but decreased the bulk modulus at the 7th nearest neighbor, making the material easier to compress. These phenomena are related to the distribution densities of the positions that hydrogen atoms can occupy on the two major slip families, {110} and {112}, at different nearest neighbors distinguished by distances.
Highlights
In the manufacturing or service life of structural materials, such as iron and steel, a small number of hydrogen atoms dissolved in the matrix will change the structures even under extremely low loads, seriously reducing the mechanical properties and causing sudden failures and fractures, which are known as hydrogen embrittlement (HE) [1,2,3,4]
The Fe–Fe interaction is described by the embedded atom method (EAM) potential developed by Mendelev [36], and the
We used atomistic simulation methods combined with clustering to study the influences of the concentration and microscopic distribution of hydrogen atoms on the elastic moduli in the interstitial solid solution of hydrogen in α-Fe
Summary
In the manufacturing or service life of structural materials, such as iron and steel, a small number of hydrogen atoms dissolved in the matrix will change the structures even under extremely low loads, seriously reducing the mechanical properties and causing sudden failures and fractures, which are known as hydrogen embrittlement (HE) [1,2,3,4]. HE affects the strength of materials and is related to the interactions between hydrogen and dislocations. The hydrogen-enhanced decohesion (HEDE) mechanism suggests that the accumulated hydrogen atoms under stress will reduce the lattice strength or surface binding [3,5,6]. Mechanism, hydrogen promotes the emission, multiplication, and motion of dislocations, which cause the localization of shears and slips, suppress the cross slips and promote planarity of the shears and slips, causing HE [2,7,8,9]. In the bulk of pure iron and ferroalloys, both softening and hardening can be caused when hydrogen is uniformly distributed, which is generally considered to be determined by the interaction between hydrogen and dislocations
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