Method for computing twin-crystal forming ability of solid solution materials

Abstract

The invention belongs to the technical field of twin-crystals, and discloses a method for computing the twin-crystal forming ability of solid solution materials. The method for computing the twin-crystal forming ability of the solid solution materials includes computing interaction between solute atoms and key point general plant stacking faults by the aid of first-principle theory periodic super-crystal cell processes when the solute atoms are doped in a plurality of adjacent layers of atoms; computing influence of the solute atoms with different levels of concentration in magnesium solid solution on general plane stacking fault energy by the aid of uniform distribution models; computing influence of the solute atoms with the different levels of concentration on the twin-crystal forming ability of the magnesium solid solution by the aid of crystal boundary induction twin-crystal models to obtain results which perfectly conform to experimental results. The method has the advantages that elements with the optimal influence on the twin-crystal forming ability of metal can be quickly and accurately found out, accordingly, the cost of experimental research can be saved, and theoretical guidance with significance on improving high-toughness alloy materials can be obtained.

Description

technical field [0001] The invention belongs to the technical field of twins, and in particular relates to a method for calculating the twin formation ability of solid solution materials. Background technique [0002] As the lightest metallic structural material, magnesium alloys hold great promise in reducing the weight of cars and aircraft, improving fuel efficiency and making them more environmentally friendly. However, the low ductility and strength of magnesium alloys still limit its wide application. The stress required to activate the basal slip of magnesium alloys at room temperature is much lower than that of its prismatic and conical slip surfaces. Generally, magnesium alloys fracture at an early stage of plastic deformation due to the strain concentration caused by the accumulation of basal plane dislocations in front of obstacles. It has recently been reported that the ductility of Mg is largely improved by adding small amounts of rare earth elements (RE) at ro...

AI Technical Summary

Problems solved by technology

However, so far there have been few theoretical studies on the effect of solute concentration on the twinning ability of metals

[0003] In summary, the problem existing in the existing technology is that the generalized planar fault energy GPFE of the solid solution calculated directly by the supercell method cannot accurately calculate the influence of solute atoms on the twin formation ability of the solid solution

The main difficulty is that according to the current computer memory and computing speed conditions in the world, the distribution of solute atoms in the unit cell cannot be accurately described when calculating the solid solution generalized planar fault energy GPFE due to the small unit cell when calculating with the supercell method

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