深冷处理对冷轧铜合金组织与性能的影响

Influence of a deep cryogenic treatment on the microstructure and properties of a cold rolled Cu-based alloy

摘要:

采用扫描电子显微镜、透射电子显微镜、X射线衍射仪、万能试验机及电阻率测试仪等研究了深冷处理对冷轧Cu-1.34Ni-1.02Co-0.61Si合金组织和性能的影响。深冷处理使30 %压下率冷轧合金显微组织细化和均匀化，并且随着深冷处理时间增加，细化和均匀化程度不断提高。深冷处理促使固溶Ni、Co和Si等原子不断从铜基体中析出，在合金晶粒内和晶界处形成尺寸为0.1?m~1?m之间的细小弥散球形和长条形第二相颗粒。冷轧前后合金的抗拉强度、电导率和延伸率均随着深冷处理时间延长而增加，并在约36 h后趋于稳定。深冷处理48 h后，冷轧前后合金的抗拉强度、电导率和延伸率分别增加了5.4 %和4.4 %、6.7 %和8.0 %、及13.2 %和18.7 %。冷轧后合金的抗拉强度高于冷轧前；而冷轧后的电导率和延伸率低于冷轧前，但差距均随着深冷处理时间增加而缩小。经深冷处理合金拉伸断口的韧窝数量和深度比未经深冷处理合金大，且分布更加均匀。

Abstract:

The influence of deep cryogenic treatments (DCT) on the microstructure and properties of a cold rolled Cu-1.34Ni-1.02Co-0.61Si alloy was investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), an X-ray diffractometer (XRD), a mechanical testing machine and a low resistance tester. The DCT refined and homogenized the microstructure of the alloy after cold rolling at 30 % reduction. The grain refinement of the alloy became more obvious and the microstructure distribution became more uniform with increasing DCT time. The DCT promoted the precipitation of the solid solution elements Ni, Co and Si from the Cu matrix to form many fine and evenly distributed 0.1?m~1?m spherical and strip second phase particles in the grain and grain boundary. The tensile strength, conductivity and elongation of the alloy before and after cold rolling at 30 % reduction increased with increasing DCT time, and tended to be stable at about 36 h. After DCT for 48 h, the tensile strength, conductivity and elongation of the alloy before and after cold rolling increased by 5.4% and 4.4%, 6.7% and 8.0%, 13.2% and 18.7% respectively. The tensile strength of the alloy after cold rolling was higher than that before cold rolling. The conductivity and elongation of the alloy after cold rolling was lower than that before cold rolling. However, the both differences decreased with increasing DCT time. The dimple quantity and depth of the alloy with DCT were larger, and the dimple distribution was more uniform than those without DCT.