Ultra-fine grain refining agent prefabricated block and process for preparing same

Abstract

The invention is an ultrafine crystal particle refiner prefabricated block and its preparing technique, containing the components in weight percent: Ti 20-50%, C 4.5-11% and the rest Al, where Ti-C ratio is 4.5 : 1; (1) making ball milling and mixing the Ti, C and Al powders in the above proportion under the protection of inert gas; (2) making cold-pressing on the mixed powder into powder blanks; (3) storing these powder blanks in the inert gas; (4) making high-temperature reaction and sintering on these powder blanks and cooling them so as to obtain the needed in-situ self-generating TiC / Al composite ultrafine crystal particle refiner prefabricated blocks. These prefabricated blocks have high compactibility and no thermal nonstable phase, and the produced TiC has fine particles, clean surface and a good coherent effect on Al.

Description

technical field [0001] The invention relates to a refiner prefabricated block and its preparation process, in particular to an in-situ authigenic TiC / Al composite material ultrafine grain refiner prefabricated block and its preparation process. belongs to the field of materials. Background technique [0002] The wide application of aluminum and aluminum alloys puts forward stricter requirements on its properties, and grain refinement is one of the important means to obtain fine and uniform equiaxed grains and improve the strength and plasticity of materials. Since TiC and Al have the same face-centered cubic crystal structure, similar lattice constants (the lattice constant of TiC is 0.43189nm, and the lattice constant of Al is 0.4049nm), and has a good coherent effect, it can be used as a grain refiner At the same time, because the Al-Ti-C grain refiner overcomes the defects of Al-Ti-B, its heterogeneous nucleation core TiC is more than TiB 2 The aggregation tendency is s...

AI Technical Summary

Problems solved by technology

The self-propagating method of high-temperature synthesis of grain refiners has its unique advantages, but there are still the following deficiencies: ①The reaction is difficult to control, and the content, shape and size composition of TiC in the grain refiner cannot be effectively controlled; ②The reaction obtained The density of the grain refiner is not high enough, the porosity is large, and the melting of aluminum and aluminum alloy is easy to cause the melt to absorb gas; ③In industrial production, it takes a long time to melt the grain refiner, which increases the melt absorption. Gas and the probability of generating harmful oxidized inclusions and waste energy, reduce production efficiency, thus limiting the application of industrial production

At present, there is no literature report on the industrial production of grain refiner by using high temperature vacuum reaction to sinter the prefabricated block of grain refiner combined with stirring casting