Porous preform, preparation method thereof, foam metal and preparation method thereof

Abstract

The invention discloses a preparation method of a porous preform. The preparation method comprises the following steps of S100, stacking inorganic salt particles in a container with a closed bottom end to form an inorganic salt particle accumulation body; S200, enabling the inorganic salt particle accumulation body to have initial compactness in the container by adopting a compaction method; S300,applying a downward constant pressure of 1-10 MPa to the upper part of the inorganic salt particle accumulation body, heating the container filled with the inorganic salt particle accumulation body to 0.2-0.8 Tm at a heating rate of 5-20 DEG C, and carrying out heat preservation; and S400, keeping the temperature for 1-8 hours, so that the inorganic salt particles creep and deform. The inventionalso discloses a porous preform. The invention further discloses a preparation method of the foam metal. The invention further discloses the foam metal.

Description

technical field [0001] The invention relates to the technical field of metal foam, in particular to a porous preform and a preparation method thereof, as well as metal foam and a preparation method thereof. Background technique [0002] In nature, there are honeycomb structures such as wood and cork, and foam structures such as bones, plant parenchyma, and sponges. These porous structures are light in weight and have excellent mechanical properties, which meet the load-bearing requirements required by organisms. Inspired by these naturally occurring porous materials, people introduce porous structures into metal materials and prepare porous metals to make metal materials meet performance requirements while reducing weight, thereby further expanding the application range of metal materials. The pores in metal foam are functional phases, which not only retain the structural material properties of metal, but also have functional material properties such as energy absorption, sh...

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Problems solved by technology

However, this process also has some inherent disadvantages: First, the porosity of metal foam is approximately equal to the packing rate of the porous preform, but limited by the packing rate of particles, usually the porosity of metal foam prepared by this method does not exceed 70%. %; In addition, the connection channels between the metal foam cells originate from the contact surface between the preform particles, but due to the limited contact area between the particles, the opening degree of the final metal foam is poor, and the flow resistance is relatively low. On the one hand, it limits its functional application, on the other hand, it makes it difficult to remove salt particles, and the unremoved salt particles will cause serious corrosion to the substrate. These factors greatly limit its lightweight and functional applications.

(B) Particle surface treatment, spraying the binder on the surface of the particles, so that the particles overlap with each other, thereby increasing the accumulation rate of the preform, but the bonding between the particles is difficult to control, and it is easy to cause the preform to partially dissolve together. Cause localized defects in the final metal foam

(C) Artificial granulation, making soft granules mechanically or manually according to a certain formula, so as to improve the compressibility of granules, but this method is time-consuming and the granulation efficiency is too low

[0006] In summary, the problems of low porosity and poor opening degree of the open-cell metal foam prepared by the particle infiltration method have not been effectively solved, which limits the large-scale industrial application of this method.

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