Method for preparing aluminum-based composite material with uniform and fine isometric crystal grains

Abstract

The invention relates to a method for preparing an aluminum-based composite material with uniform and fine isometric crystal grains, which belongs to the field of material preparation. The method is characterized by adding mixed salts of K2TiF6 and K2ZrF6 into an aluminum melt or an aluminum alloy melt to perform an in-situ reaction so as to generate small-size reinforced grains, wherein a cast structure has fine isometric crystals; the addition amount of the mixed salts of the K2TiF6 and the K2ZrF6 is 0.5 to 3 weight percent of the total mass of aluminum liquid; and the K2TiF6 and the K2ZrF6 are mixed in a molar ratio of Ti to Zr of 0.5-2:1. The method has the advantages that: a cast composite material matrix has the characteristics of a fine isometric crystal structure; the reaction efficiency is high; the cost of the mixed salts is low; the pollution is low; and the process is simple and easy to operate and is convenient to form industrial scale production.

Description

technical field [0001] The invention relates to a preparation method of a metal matrix composite material with micron particle strengthening and uniform fine equiaxed crystal structure, belonging to the field of material preparation. Background technique [0002] The fine and equiaxed grain structure of the metal can improve the mechanical properties and process properties of the material. According to comprehensive literature reports, the common grain refinement methods are as follows: [0003] The first is the addition of grain refiners. [0004] The second is to apply vigorous agitation during the solidification process. Mechanical stirring will pollute the melt, while electromagnetic stirring equipment is large and costly, and both methods will cause aluminum liquid to absorb gas; [0005] The third is to use the method of large deformation processing to promote grain refinement by performing large deformation processing on the as-cast sample, multi-pass extrusion or r...

AI Technical Summary

Problems solved by technology

[0007] Al-Ti-C-(RE0.3-0.5wt.%) system, the disadvantage is that the aluminum melt and carbon are not wet, alloying is difficult, the construction period is long, and the energy consumption is large;

[0008] Al-RE (0.3-0.5wt.%) series, high rare earth activity, difficult to control the yield, difficult to smelt;

[0009] The disadvantage of Al-Ti-B system is that the melting temperature of the intermediate alloy is high, because TiB 2 It is a high-temperature stable phase, and the smelting temperature generally exceeds 1000 ° C. At this time, part of the formed Al 3 Ti will grow into slender strips, which will split the matrix and affect the fine-grain effect;

[0010] Al-Ti system, the disadvantage is that the generated Al 3 The shape of Ti is difficult to control, and it is easy to grow into strips, which affects the fine-grain effect

Chinese invention patent 200910055605.X proposes to achieve grain refinement by rolling and deforming ultra-high-purity aluminum, which requires a continuous process of cryogenic-rolling-returning-heat preservation, which is different from the fine-grain mechanism of the present invention, and the process is cumbersome , long cycle, high cost, high cost of industrial scale preparation

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