连续柱状晶组织纯铜室温超延展变形机理

Extreme plastic extensibility mechanism of continuous columnar-grained copper at ambient temperature

通过下引式连续定向凝固设备,调控合理的工艺参数制备出表面光洁、单一?100?取向的柱状晶铜杆。然后经室温拉拔(不经过中间热处理),表现出超延展变形。通过组织观察和性能分析,发现其塑性变形可以分为3个阶段:一般硬化阶段(ε≤4.13),低硬化速率阶段(4.13≤ε≤10.16),部分亚微米等轴晶粒形成阶段(ε≥10.16)。每个阶段的塑性变形行为各有不同,各有其特点。研究结果全面地概括连续柱状晶组织铜杆在室温拉拔过程中的变形机理,同时也为超细铜丝的制备提供必要的理论依据。

The smooth surface and single ？100？ oriented columnar-grained copper rods were prepared by downward continuous unidirectional solidification equipments with reasonable process parameters, then, the copper rods were drawn at ambient temperature（without intermediate heat treatment）, which exhibits the extreme plastic extensibility. The results show that the plastic deformation of the copper rod can be divided into three different stages by observation of its microstructure and properties, general hardening stage（ε≤4.13）, low hardening rate stage（4.13≤ε≤10.16）. Some submicron equiaxed grain forming stage（ε≥10.16）. Each stage of the plastic deformation behavior is different and has its own characteristics. Not only the drawing mechanism of continuous columnar-grained copper rods at ambient temperature was comprehensively summarized, but also the necessary theoretical basis for the preparation of ultrafine copper wire was provided.