Microstructural Improvement of Eutectic Al + Mg(2)Si Phases on Al–Zn–Si–Mg Cast Alloy with TiB(2) Particles Additions

In this study, the effects of adding TiB(2) particles to eutectic Al + Mg(2)Si phases in aluminum alloys were analyzed. The eutectic Al + Mg(2)Si phases were modified effectively when a large amount of TiB(2) was added, and changes in the shape, size, and distribution of the eutectic Al + Mg(2)Si phases were confirmed using a polarizing microscope and FE-SEM. The crystal structure of the TiB(2) particles and Mg(2)Si phases were analyzed using HR-TEM, and the analysis confirmed that the TiB(2) particles can act as heterogeneous nucleation sites. This paper intends to clarify the principle of phase modification of the eutectic Al + Mg(2)Si phases by TiB(2) particles and proposes a new mechanism to improve Mg(2)Si phase modification when TiB(2) particles are added.