Reverse deposit composite material and its preparation method

Abstract

A composite material is prepared from basic material and powdered material by reverse deposition. Its preparing process includes heating the basic material until it becomes liquid, filling in mould cavity at a temp lower than the smelting point of powdered material, filling the powder in the mould cavity, floating the powder in the liquid and then depositing in the liquid, and solidifying. Its advantage are fine and uniform crystal grains, and high productivity.

Description

(1) Technical field [0001] The invention relates to the technical field of preparation methods and devices of composite materials, in particular to a reverse deposition composite material and a preparation method thereof. (2) Background technology [0002] At present, the manufacturing method of the alloy is to melt the various component metals that constitute the alloy material and mix them in a liquid state. The components of the mixed metal liquid are made as uniform as possible by the method of stirring, and the method of adding a modifier is used to increase the number of crystal nuclei to achieve crystal grains. purpose of refinement. Since the liquid metal as a whole changes from a liquid state to a solid state, it must go through the process of nucleation, crystallization, and grain growth, and the location and quantity of nucleation are very random, and the microstructure is difficult to control. Common defects in casting such as Structural defects such as shrinkag...

AI Technical Summary

Problems solved by technology

The method of stirring casting with powder particles in the liquid is to mechanically stir above the opening of the crucible to generate a vortex in the molten metal to introduce powder particles. The disadvantage of this method is that when the powder particle size is less than 10 μm, it cannot be passed through the stirring method Let the powder enter the metal liquid, and the powder cannot be evenly distributed in the matrix material, and the microstructure is not repeatable

The preparation methods of the above-mentioned composite materials cannot make the powder evenly distributed in the matrix material, the proportion of the powder material in the composite material is small, and the microstructure is not repeatable, so the stability and reliability of the performance of the composite material cannot be guaranteed. Guaranteed

Disadvantages of the casting method: On the one hand, the finer the reinforcement particles, the higher the specific mechanical properties of the corresponding material; on the other hand, the more serious the agglomeration of the finer particles, it is difficult to obtain the optimal performance of the material by ordinary casting methods

For example, iron-based powder forming parts are generally sintered at 1080°C for two hours, which consumes a lot of energy, and the green body will inevitably be deformed during sintering, which will affect the accuracy of the part.

For nanocrystalline powder, the crystal grains are easy to grow during the sintering process, making it difficult to maintain the properties of nanocrystals

Due to the large number of pores in the powder sintered material, the material is discontinuous and the subsequent machining performance is poor