Production of Al-Zr Master Alloy by Electrolysis of the KF-NaF-AlF3-ZrO2 Melt: Modifying Ability of the Master Alloy

In prior works, a novel method for continuously obtaining Al-Zr master alloys from oxide raw materials by electrolysis of a low-melting electrolyte based on the KF-NaF-AlF3-ZrO2 system at 800 degrees C to 820 degrees C was proposed. In the present work, the method for preparing the Al-Zr master alloy proceeded in an enlarged 100 A electrolyzer and the obtained master alloy was applied for grain refinement and improvement of its aluminum alloy properties. The modifying ability of the master alloy was studied, drawing on the example of the Al-Si-Fe alloy. Different amounts of the Al-Zr master alloy with a content of 10 wt pct zirconium were added to the Al-Si-Fe alloy at 900 degrees C. The effect of the zirconium content in the aluminum alloy and its cooling rate on its structure and properties was revealed. It was found that the addition of zirconium to the alloy refined the grain by 4 to 5 times without changing its shape or structure. A study of the joint effect of alloying and rate cooling indicated that a grain size reduction of up to 5 mkm can be achieved by these procedures.

Automated summary

A novel method for continuously obtaining Al-Zr master alloys from oxide raw materials was proposed and applied in grain refinement and improvement of aluminum alloy properties. The addition of zirconium to the alloy significantly refined the grain size, while a joint effect of alloying and rate cooling could achieve further grain size reduction.