Molecular dynamics simulation of the effect of solute atoms on the compression of magnesium alloy

Magnesium alloys have a wide range of application values. To design and develop magnesium alloys with excellent mechanical properties, it is necessary to study the deformation process. In this paper, the uniaxial compression (UC) process of AZ31 magnesium alloy with different solute atom content is simulated by the molecular dynamics method. The effect of the solute atom on the uniaxial compression of magnesium alloy is investigated. It is found that solute atoms can inhibit the grain refinement of magnesium, can effectively improve the plastic strength of the alloy, can change the lattice distortion during uniaxial compression of magnesium alloy, can inhibit the generation of BCC structure, and can slow down the increase of FCC structure and dislocation density. The direction of the FCC structure diffusion is 90° to the grain boundary direction. Shockley partial dislocations are generated around the FCC structure. The direction in which the FCC structure spreads is consistent with the direction in which Shockley partial dislocations move.

Distortion energy-electronic energy compensation determines the nature of solute interactions with irradiation induced vacancies in ferritic steel

Fundamental knowledge of vacancy–solute atom (in particular, Cu and Ni) interactions at the electronic level is of utmost importance to understand experimentally observed Cu-precipitation in reactor pressure vessel (RPV) steel.

Generalized Stacking Fault Energy of {10-11} Slip System in Mg-Based Binary Alloys: A First Principles Study

In this work, the generalized stacking fault energies (GSFEs) of {10-11}<11-23> slip system in a wide range of Mg-X (X = Ag, Al, Bi, Ca, Dy, Er, Gd, Ho, Li, Lu, Mn, Nd, Pb, Sc, Sm, Sn, Y, Yb, Zn and Zr) binary alloys has been studied. The doping concentration in the doping plane and the Mg-X system is 12.5 at.% and 1.79 at.%, respectively. Two slip modes (slip mode I and II) were considered. For pure magnesium, these two slip modes are equivalent to each other. However, substituting a solute atom into the magnesium matrix will cause different effects on these two slip modes. Based on the calculated GSFEs, two design maps were constructed to predict solute effects on the behavior of the {10-11}<11-23> dislocations. The design maps suggest that the addition of Ag, Al, Ca, Dy, Er, Gd, Ho, Lu, Nd, Sm, Y, Yb and Zn could facilitate the {10-11}<11-23> dislocations.

Achieving Ultrahigh Hardness in Electrodeposited Nanograined Ni-Based Binary Alloys

Annealing hardening has recently been found in nanograined (ng) metals and alloys, which is ascribed to the promotion of grain boundary (GB) stability through GB relaxation and solute atom GB segregation. Annealing hardening is of great significance in extremely fine ng metals since it allows the hardness to keep increasing with a decreasing grain size which would otherwise be softened. Consequently, to synthesize extremely fine ng metals with a stable structure is crucial in achieving an ultrahigh hardness in ng metals. In the present work, direct current electrodeposition was employed to synthesize extremely fine ng Ni-Mo and Ni-P alloys with a grain size of down to a few nanometers. It is demonstrated that the grain size of the as-synthesized extremely fine ng Ni-Mo and Ni-P alloys can be as small as about 3 nm with a homogeneous structure and chemical composition. Grain size strongly depends upon the content of solute atoms (Mo and P). Most importantly, appropriate annealing induces significant hardening as high as 11 GPa in both ng Ni-Mo and Ni-P alloys, while the peak hardening temperature achieved in ng Ni-Mo is much higher than that in ng Ni-P. Electrodeposition is efficient in the synthesis of ultrahard bulk metals or coatings.