Uncovering the influence of common nonmetallic impurities on the stability and strength of a Σ5 (310) grain boundary in Cu

Combined effects of nonmetallic impurities and planned metallic dopants on grain boundary energy and strength

“…First-principles calculations were performed with the Vienna ab-initio simulation package (VASP) using the projector augmented wave approach [48] and the Perdew-Burke-Ernzerhof exchange-correlation generalized gradient approximation (GGA) functional [49]. A plane-wave cutoff energy of 350 eV, kpoint meshes of 3 × 2 × 1, convergence energy of 10 -5 eV/atom, and convergence atomic force of 0.01 eV/Å were used for all calculations to balance the accuracy and efficiency of calculations [35]. The atoms in grain boundary model were fully relaxed during the process of structural optimizations, except that the z coordinate of atoms on the outermost layers were fixed.…”

“…Wu et al [29] found that the strengthening effect of metallic dopants on W grain boundaries depended on the type of grain boundary structure and the atomic radius of the added dopant. At the same time, the effect of impurities on similar properties has been an active area of research [22,[32][33][34][35][36]. For example, the incorporation of a small quantity of nonmetallic H impurities can cause embrittlement [32][33][34].…”

“…While this work is motivated by the need for better nanostructured materials, alterations to the grain boundary energy and strength will also be important for coarse-grained materials. [32,35]), making it an appropriate model for a systematic investigation. Prior studies have shown that the substitutional sites are the preferred sites for the metallic dopants, while the interstitial sites are the preferred sites for nonmetal impurities [30,35].…”

“…[32,35]), making it an appropriate model for a systematic investigation. Prior studies have shown that the substitutional sites are the preferred sites for the metallic dopants, while the interstitial sites are the preferred sites for nonmetal impurities [30,35]. The grain boundary specimen has dimensions of 7.267 × 11.490 × 28.086 Å 3 and contains 112 atoms.…”

“…Hereafter, we will refer to metallic atom additions as "dopants" and nonmetallic atoms as "impurities." Since the atomic radius and electronegativity of dopants and impurities might be key factors for alteration of grain boundary energy and strength [29,35,45] and a range of these parameters is sought, we choose Al, Zn, Zr, Nb, Mo, Pd, Ag, and Bi as the metallic dopants while selecting H, B, C, N, O, Si, P, and S as the nonmetallic impurities. The atomic radii [46] and electronegativities [47] of these choices are listed in Table 1, along with the values for Cu.…”