连续铸造铜单晶棒材的工艺参数与性能

Technologic Parameter and Properties of Copper Single Crystal by Continuous Casting

在自制水平单晶连铸设备上研究铜单晶的连铸技术。结果表明，当铸型温度Ｔｃ２＝１１００～１１２０℃、固液界面前沿温度梯度ＧＬ＝５～６℃／ｍｍ、连铸速度Ｒ＝２０～３０ｍｍ／ｍｉｎ时，可获得镜面状的单晶铸棒。连铸时固液界面位于铸型内部，并向熔体呈凸出形状。铸棒内的杂晶是由于铸型温度低于铜的熔点（１０８３℃）和连铸速度增加所致，当Ｒ大于３０ｍｍ／ｍｉｎ时形成单向凝固的柱状晶铸棒。单晶的生长方向为［１００］，结晶面为（２００）。铜单晶与多晶铸棒相比，抗拉强度降低了２０．８５％，屈服强度降低８６．５４％，延伸率增加了８０．２４％，断面收缩率增加了３．９４５倍；电阻率降低了１５．５７％。因此，连铸铜单晶具有优异的塑性和低电阻率。

he continuous casting technology of copper single crystal have been studied using a home made equipment.Experimental results show that single crystal copper rod of surface smooth like a mirror can be obtained on condition that the temperature gradient of solidliquid interface front(GL) is 5～6℃/mm,the temperature of mould is 1100～1120℃ and the casting speed is 20～30mm/min.The solidliquid interface is a convex shape and the intersecting line of the convex interface and the rod surface is controlled at the inside of the mold.Stray crystals(equiaxed grains and columned grains)in surface of rod is formed because of lower mould temperature (<1083℃) at the lication of the solidification front and increment of casting speed.However,at casting speed above 30mm/min,the rod contained unidirectional columnar grains.During solidification,the direction of crystallization is ,the face of crystallization is (200).The tensile strength and the yield strength of the single crystal copper rod is lower 20.85% and 86.54% respectively,but the elongation and the reduction in crosssection area is increased by 80.24% and 394.50% respectively than that of the polycrystal rod.The resistivity of single crystal copper rod is 15.57% lower than these of polycrystal rod.The single crystal copper rod have excellent properties for cold working and lower resistivity which has broad prospects of application in electron industry and communciation mechnology.