Method for preparing Al-Ti-B grain refiner

Abstract

The Al-Ti-B crystal grain fining agent for metal material has the components including Ti 2-10 wt%, B 2 wt% and Al the rest. The preparation process includes the steps of: mixing industrial pure potassium fluorotitanate and potassium fluoroborate homogeneously, heating to melt industrial pure aluminum, adding the mixed salt into aluminum melt and covering the surface of the melt with KCl, introducing ultrasonic wave to over the melt, skimming slag, cooling the melt naturally while continuous ultrasonic treatment until the intermediate alloy solidifies completely to obtain the Al-Ti-B crystal grain fining agent. The present invention has short preparation period and less oxidation loss of aluminum melt, and the obtained casting structure has fine TiAl3 grains of homogeneous size below 20 microns and TiB2 grains with clear contour. The Al-Ti-B crystal grain fining agent is used in preparing industrial pure aluminum with crystal grains smaller than 120 microns.

Description

technical field [0001] The invention relates to a preparation method of a grain refiner in the field of metal materials, in particular to a preparation method of an Al-Ti-B grain refiner. Background technique [0002] At present, in the industrial production of aluminum and its alloys, the method of adding Al-Ti-B master alloy to the melt is generally used to achieve the purpose of grain refinement, and the preparation of Al-Ti-B master alloy is generally used at home and abroad. Fluoride salt reaction method. [0003] Found through literature search to prior art, B.S.Murty is in " International Materials Reviews " (" International Materials Review ") magazine, the article " Grain refinement of aluminum and its alloy by heterogeneous nucleation and alloying (heterogeneous nucleation of aluminum and its alloys and microalloying grain refinement)", the Al-Ti-B master alloy mentioned in this article is prepared by the fluoride salt reaction method, the general process of the f...

AI Technical Summary

Problems solved by technology

Although the master alloy prepared by this method has a certain refining effect on industrial pure aluminum and its alloys, the preparation cycle of the master alloy is long, the energy consumption is large, and the oxidation and burning of the metal is serious; the intermetallic compound TiAl in the alloy structure 3 The particles are generally relatively coarse, and the size is above 80 μm, which increases the response time of the master alloy; at the same time, the TiB in the structure plays a key role in refining 2 Particles are mostly cohesive together, showing uneven aggregated distribution

After the Al-Ti-B master alloy with this microstructure is added to the aluminum melt, the coarse TiAl 3 Increased phase dissolution diffusion time, adhesion TiB 2 The dispersion of particle aggregation is poor, so that the refinement performance of the master alloy cannot achieve the ideal effect. The as-cast grain size of industrial pure aluminum after refinement of this type of master alloy is generally greater than 150 μm