Microstructural Improvement of Eutectic Al + Mg₂Si Phases on Al-Zn-Si-Mg Cast Alloy with TiB₂ Particles Additions

In this study, the effects of adding TiB₂ particles to eutectic Al + Mg₂Si phases in aluminum alloys were analyzed. The eutectic Al + Mg₂Si phases were modified effectively when a large amount of TiB₂ was added, and changes in the shape, size, and distribution of the eutectic Al + Mg₂Si phases were confirmed using a polarizing microscope and FE-SEM. The crystal structure of the TiB₂ particles and Mg₂Si phases were analyzed using HR-TEM, and the analysis confirmed that the TiB₂ particles can act as heterogeneous nucleation sites. This paper intends to clarify the principle of phase modification of the eutectic Al + Mg₂Si phases by TiB₂ particles and proposes a new mechanism to improve Mg₂Si phase modification when TiB₂ particles are added.