# Effect of Master Alloy Based on Al and Si with Ti and B on Mechanical Properties of AlSi9 Alloy

## TL;DR

This paper studies how adding titanium and boron to aluminum-silicon master alloys improves the mechanical properties of AlSi9 alloy.

## Contribution

The study demonstrates that a master alloy with titanium and boron in AlSi7 yields the best microstructure refinement and mechanical properties.

## Key findings

- Adding titanium and boron to AlSi7 master alloy significantly refines the microstructure of AlSi9.
- Magnesium in the master alloy reduces the effectiveness of microstructure refinement.
- AlSi7 master alloy with titanium and boron provides better mechanical properties than other configurations.

## Abstract

Hypoeutectic aluminum–silicon casting alloys in their unmodified state have a coarse-grained eutectic (α + β), which results in poor mechanical properties and brittleness. Microstructure refinement and improved mechanical properties are possible, among other things, by introducing various elements and chemical compounds. The literature presents numerous studies on the modification of hypoeutectic silumins, but there are no results confirming the effectiveness of the interaction of a master alloy containing titanium and boron with its main component, which may be aluminum, aluminum with silicon, or aluminum with silicon and magnesium. This paper presents the results of microstructure refinement using titanium or boron introduced into the Al, AlSi7, and AlSi7Mg master alloys. The introduction of titanium and boron into the aluminum-based master alloy resulted in microstructure refinement and improved mechanical properties. The results indicate that the most favorable results were obtained when titanium and boron were introduced into the AlSi7 master alloy. The addition of magnesium to the master alloy AlSi7 resulted in less effective microstructure refinement of the AlSi9 silumin, which resulted in lower mechanical properties than those obtained for the master alloy without Mg.