Research on Crystal Orientation Evolvement of Continuously Unidirectionally Solidified Copper Rods during Working Process

Copper rods with diameter of 17.0 mm have been fabricated by Continuous Unidirectional Solidification (CUS) process. The metallographic results show that the microstructures of the rods are longitudinal columnar crystals and the crystal sizes range roughly among 100-200 μm. The copper rod can be worked to ultra-fine wires 19.7 μm diameter at room temperature without any heat treatments, and the size of the microstructure of the wires obtains nanometer scale. During working process, the elongation multiple of the rod is as high as 740 000 and total deformation true strain over 13.5. The copper rod containing continuous columnar crystals has exhibited excellent cold elongation deformation ability. The results of the texture tests show that the rod has strong <100> fiber texture. After worked at room temperature, texture variants of strong <100> and less strong <111> evolve in the copper wires. With increasing deformation level, the contour of <100> fiber texture decreases while <111> increases. The excellent cold elongation deformation ability and high strength of copper wires is considered to be a result of the strong <100> fiber texture, work hardening and a small quantity of <111>

Copper rods with diameter of 17.0 mm have been fabricated by Continuous Unidirectional Solidification (CUS) process. The metallographic results show that the microstructures of the rods are longitudinal columnar crystals and the crystal sizes range roughly among 100-200 μm. The copper rod can be worked to ultra-fine wires 19.7 μm diameter at room temperature without any heat treatments, and the size of the microstructure of the wires obtains nanometer scale. During working process, the elongation multiple of the rod is as high as 740 000 and total deformation true strain over 13.5. The copper rod containing continuous columnar crystals has exhibited excellent cold elongation deformation ability. The results of the texture tests show that the rod has strong <100> fiber texture. After worked at room temperature, texture variants of strong <100> and less strong <111> evolve in the copper wires. With increasing deformation level, the contour of <100> fiber texture decreases while <111> increases. The excellent cold elongation deformation ability and high strength of copper wires is considered to be a result of the strong <100> fiber texture, work hardening and a small quantity of <111> variant