Role of Si in the evolution process of Zr-rich intermetallics in Mg melt

By introducing Al-(Si-)Zr alloys into Mg melt, the evolution process of Zr-rich intermetallics was studied. Through the outside diffusion of Si from ZrSi2 and inside diffusion of Mg atoms, ZrSi2 phase was detected to evolve to SiZr and finally to MgSiZr. Along with this process, the dense particles disintegrate into smaller parts. Similar evolution behavior of Zr(Al,Si)3 phase was also found inducing by atom diffusion. However, no obvious change was detected on ZrAl3 particles in Mg melt. It is supposed that Si plays an important role in the evolution procedure of Zr-rich intermetallics. This work may provide suggestions to obtain designed phases by introducing the alloys with one matrix into another melt.