Preparation of Single Crystal Copper with Large Diameter and Evolution of Solidification Structure

Single crystal copper with large diameter is prepared in vacuum induction furnace under the protection of argon using downward continuous unidirectional solidification method. The process parameters are determined through the experiments. The effects of the process parameters on solidification structure and surface quality of the single crystal copper with large diameter are investigated. The results show that single crystal copper of Φ16 mm with bright surface can be obtained continuously and stably under the following conditions: melting temperature is 1150 ℃, outlet temperature of mold is 750 ℃, cooling water volume is 0.9 m3·h-1, cooling distance is 50 mm, and drawing speed is 0.1 to 0.15 mm·s-1. By X-ray diffraction, the orientation and competition growth of single crystal copper have been analyzed, and the crystallization surfaces of (311), (220) and (111) are eliminated sequentially during evolutionarily processing. The final growth face of single crystal copper is (200). its direction of crystallization is [100]. Effect of solid-liquid interface on crystal growth has been investigated, the micro-convex interface to liquid is the key to getting single crystal copper.