Method for preparing semi-solid slurry of Al-Si-Cu alloy induced and inoculated by misch rare earth

Abstract

Disclosed is a method for preparing semi-solid slurry of Al-Si-Cu alloy induced and inoculated by misch rare earth. The method includes the following steps that (1) an Al-Si-Cu alloy ingot is put in a graphite crucible for overheating melting, refining and deslagging; (2) Al-5Pr-5Ce intermediate alloy coated with aluminum foil paper is added into a melt, the adding amount accounts for 3wt%-9wt% of the amount of the melt, then the furnace temperature is increased to 760-770 DEGC, and heat preservation is conducted for 15-20 min; (3) a preheated ultrasound amplitude transformer probe is put in the melt for intermittent ultrasound treatment, the ultrasound interval is 1-2s each time, the ultrasound releasing time is 2.0-2.5s each time, the ultrasound power is 1.0-2.0kw, the ultrasound frequency is 20kHz, and the total ultrasound treatment time is 3-5 min; and (4) the furnace temperature is decreased to 585-610 DEG C, heat preservation is conducted for 8-10 min, the intermittent ultrasound treatment is performed again under the same conditions for 60-100s, and water quenching is performed immediately after ultrasound treatment is finished. The crystal grains of the obtained semi-solid structure are thinner, round and uniformly distributed, the demand for semi-solid rheoforming is completely met, the operation is simple and convenient, the method is safe and reliable, and three-waste pollution is avoided.

Description

Technical field [0001] The invention belongs to the technical field of material preparation and relates to a preparation method of semi-solid slurry. Background technique [0002] Semi-solid forming technology is a near-net forming technology with high production efficiency and is known as a new generation of metal forming technology in the 21st century. Compared with traditional liquid casting, semi-solid casting has less machining volume, lower processing temperature, lower solidification shrinkage, and significantly improved structure and performance. Studies have shown that rare earths have unique electronic layer structure and physical and chemical properties, and have super-strong spin coupling characteristics. Adding a small amount of rare earths to aluminum alloys can induce gestation. The microstructure and mechanical properties of the alloys are all It can be improved to a certain extent, and it can also purify and degas the melt. In addition, under the same condition...

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Problems solved by technology

Among them, the mechanical stirring method has the following disadvantages: the molten metal is easily polluted and corroded by the stirrer, and it is easy to be involved in gas and inclusions after a long time, and there is a stirring dead zone, which affects the quality of the semi-solid billet

The isothermal heat treatment method has the following disadvantages: the process parameters such as heating temperature and holding time are difficult to control

The electromagnetic stirring method has the following disadvantages: large equipment investment, large electromagnetic gap of the device, serious magnetic flux leakage, and a large part of the energy cannot be used for stirring the metal melt, which greatly increases the production cost

The near-liquidus method has the following disadvantages: the preparation cycle is long, and it is difficult to accurately control the pouring temperature of the melt

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