Method for preparing nano particle enhanced magnesium-based composite material

Abstract

The invention discloses a method for preparing a nano particle enhanced magnesium-based composite material, and relates to the technical field of magnesium-based composite material preparation. A two-step synthesis method is adopted in the method, wherein in the first step, a master alloy containing nano enhanced particles is generated by in-situ reaction in an aluminum melt under the composite action of a pulse magnetic field and a pulse electric field; and in the second step, after magnesium or magnesium alloy melt is melted, the prepared master alloy is added into the melt, and uniform mixing of the master alloy in the melt and dispersion of the particles are promoted by the external electric and magnetic fields. The method has the main advantages that: the particle phase in the magnesium-based composite material is controlled in nano scale and dispersed uniformly; compared with a one-step direct synthesis method, the number of the particle phase in the composite material prepared by adopting the method is easily accurately regulated and controlled, the melting time of the magnesium melt is shortened, and oxidation and combustion loss of the magnesium are controlled; and in addition, low air suction amount of the magnesium melt is favorable for controlling the tissue defects such as loose, hole shrinkage and the like of the magnesium-based composite material.

Description

technical field [0001] The invention relates to the technical field of preparing magnesium-based composite materials, in particular to a method for preparing nanoparticle-reinforced magnesium-based composite materials. Background technique [0002] As the lightest metal-based structural material, magnesium-based composites have very high specific strength, specific stiffness, good high temperature resistance and damping performance, and are easy to cast and machine. They are widely used in aerospace, navigation, automobile and other industrial and military equipment manufacturing and other fields have broad application prospects; the performance of particle-reinforced magnesium-based composites is not only related to the type of reinforcing phase, but also closely related to the shape, size and distribution of the particle-reinforced phase. These factors all depend on the magnesium-based composite. The preparation method of the material; the preparation of particle-reinforce...

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Problems solved by technology

[0003] There are two main methods for preparing particle-reinforced magnesium-based composites by in-situ synthesis: (1) mixed salt and melt direct reaction synthesis, for example: Chinese Patent: 03116169.3, Invention Name: "Preparation of In-Situ Reinforced Magnesium-Based Composite Material Process with Mixed Salts" proposes to prepare magnesium-based composite materials by using mixed salt and melt reaction method, that is, the mixed salt is directly added to the magnesium-based melt, and then cast after stirring The in-situ magnesium-based composite material is obtained. The disadvantage of this method is that the mixed salt is added concentratedly, the local reaction is too severe, the temperature is difficult to control, the particle phase grows and the cluster is serious, and it is easy to cause the oxidation of magnesium at high temperature, combustion loss and gas absorption. ; (2) Prefabricated master alloy-secondary synthesis method, for example: Chinese patent: CN 101177742A, title of invention: "Method for preparing TiB2 particle-reinforced magnesium-based composite material in situ" proposes to use prefabricated master alloy Alloy method, first in the aluminum melt through the in-situ reaction to prepare the parent alloy containing the particle reinforcement phase, and then add it to the magnesium melt to make the composite material; the advantage of the second method is that the in-situ reaction and magnesium The melt is separated to prevent the burning of the magnesium melt when the local temperature is out of control, but the disadvantage is that the particle phase will show obvious clustering and growth in the magnesium-based melt, which seriously affects the performance of the composite material

[0004]Therefore, the main disadvantage of the current method of in-situ synthesis of particle-reinforced magnesium-based composites is that when using the direct reaction method of mixed salt and magnesium-based melt, the in-situ The reaction synthesis process is difficult to effectively control; and when the prefabricated master alloy-secondary synthesis method is used, the cluster and growth of the particle reinforcement phase are difficult to control, and the particle size cannot be controlled at the micro-nano scale; in the prior art, mechanical stirring is used to solve the above-mentioned problems. The problem has a certain effect, but because mechanical stirring is easy to damage the flame retardant layer on the magnesium melt, and it is easy to destroy the inert atmosphere in the preparation process, which is easy to cause uncontrolled combustion. In addition, for the clusters of the particle phase, mechanical stirring cannot guarantee the melting The pool is evenly stirred, which has very limited effect on controlling the growth of clusters and particle phases; therefore, it is necessary to introduce new reaction control and particle cluster and growth control techniques in the in-situ synthesis of particle-reinforced magnesium-based composites.

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