Preparation method for aluminum alloy semi-solid slurry induced and impregnated by modificator

Abstract

A preparation method for aluminum alloy semi-solid slurry induced and impregnated by a modificator comprises the following steps that (1) an Al-Si-Cu alloy ingot is placed into a graphite crucible to be subjected to fusion, refining and slag removal; (2) small pieces of Al-Sr intermediate alloy are added into the fondant, the mass fraction of Sr in the Al-Sr intermediate alloy is 9 wt.%-11 wt.%, and the mass fraction of the Sr in the fondant is 0.01 wt.%-0.09 wt.%; (3) the temperature is increased to 760-770 DEG C, heat preservation is conducted for 15-20 min, then a preheated ultrasonic amplitude-change pole probe is placed in the fondant, ultrasounds are released intermittently, the ultrasound interval of each time is 1-2 s, the ultrasounds are released for 2.0-2.5 s each time, the power is 1.0-2.0 kw, the frequency is 20 kHz, the total ultrasound time is 3-5 min, then the temperature is decreased to 585-610 DEG C, and standing and heat preservation are conducted for 8-10 min; and (4) intermittent ultrasound treatment is conducted on the fondant again, the ultrasound conditions are identical to those in the step (3), the total ultrasound time is 60-100 s, and water quenching is conducted immediately after the ultrasound treatment is completed. Grains of semi-solid structures obtained through the method are finer, rounder, more complete and more uniform in distribution and fully meet the requirements for semi-solid rheoforming, operation is easy and convenient, safety and reliability are achieved, and three-waste pollution is avoided.

Description

technical field [0001] The invention belongs to the technical field of metal 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, lower processing temperature, less solidification shrinkage, and significantly improved structure and performance. Studies have shown that adding a small amount of modifiers (such as Na, K, Ba, Sr, Re, etc.) to aluminum alloys can not only achieve better refinement and modification effects, but also have the effect of purifying the melt and degassing, among which Sr is an ideal metamorphic material, its refinement effect is obvious and the metamorphic effect has a long-term effect, that is, the effect of inducing inoculation is very good...

AI Technical Summary

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

Among them, the electromagnetic stirring method has the following disadvantages: the investment in equipment is large, the electromagnetic gap of the device is large, the magnetic flux leakage is serious, 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

Images