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

Abstract

A prefabricated block of an ultrafine grain refiner and a preparation process thereof belong to the field of materials. The composition of the prefabricated block of the ultra-fine grain refiner of the present invention and its weight percentage are 20-50% of Ti, 4.5-11% of C, and the rest is Al, wherein the ratio of Ti:C is 4.5:1; (1) according to the above ratio The good Ti powder, C powder, and Al powder are ball milled and mixed under the protection of an inert gas; (2) the mixed powder is cold pressed into a powder blank; (3) the pressed powder blank is stored under the protection of an inert gas; (4) The powder blank is sintered in a high-temperature vacuum reaction and then cooled to obtain the desired in-situ authigenic TiC / Al composite ultrafine grain refiner prefabricated block. The present invention utilizes the superfine grain refiner prefabricated block of the high-temperature vacuum reaction sintering method, and the composite material prefabricated block obtained through the high-temperature vacuum reaction sintering process has high density, no thermodynamically unstable phase, and the TiC particles produced by the reaction are fine, the surface is clean, Good coherent effect with aluminum.

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