Aligned Co-Co2 Si eutectics

The addition of W, Ta, or Al to Co-rich Co-Si alloys suppresses the formation of Co₃Si and produces stable eutectics between the Co₂Si and the Co-rich solid-solution phase. The Co-Si-W and Co-Si-Ta alloys solidified as three-phase eutectics. The Co-Si-Al alloy solidified as a two-phase eutectic, but a third phase precipitated on cooling. Interesting morphological changes were produced by epitaxial precipitation of Co₂Si from solid solution during cooling.