The microstructure of Cu-Zr alloy by directional solidification

In-situ composite of Cu-12.25Zr alloy was prepared by directional solidification technique in this paper. And the microstructures of the composites were observed by scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction. The results show that the effect of growth velocity on the microstructure of the composite is important under certain temperature gradient. With the increase of growth velocity, the shape of microstructure develops into laminate, bar and dendrite in turn. The main second phase in the composite is Cu 5Zr besides a little Cu 8Zr 3 and Cu 10 Zr 7, and the Cu 5Zr phase has certain orientation relationship to copper matrix. The enrichment of Zr element is also observed at the tip of the dendrites.