铜导线高温拉伸组织与力学性能分析

Analysis of Microstructure and Mechanical Properties of Copper Wire at High Temperature Tensile

采用热模拟法对铜导线做100℃~250℃的高温拉伸试验,并用SEM、金相显微镜、TEM对不同拉伸温度下的断口形貌、金相组织、位错结构进行分析,并对力学性能进行研究。随着拉伸温度升高,断口形貌由纤维状向礁石状变化,韧窝变小,铜导线由韧性断裂变为脆性断裂,温度的增加使铜导线的塑性降低;100℃~200℃随着温度升高,晶粒逐渐变得粗大,但250℃时发生回复再结晶,晶粒变小。不同温度,晶粒被拉长,但晶粒具有明显的方向性,不同的晶粒取向不同、滑移方式不同;随着温度升高,位错在析出界面上塞积,拉伸后位错密度明显增加,即拉伸变形促进位错增殖。

High temperature tensile test of copper wire was carried out at 100℃~250℃by thermal simulation.The fracture morphology,metallographic structure and dislocation structure at different tensile temperatures were analyzed by SEM,metallographic microscope and TEM,and the mechanical properties were studied.With the increase of tensile temperature,the fracture morphology changes from fiber to reef,dimples become smaller.Copper wire changes from ductile fracture to brittle fracture,and the increase of temperature leads to the decrease of ductility of copper conductors.At 100℃~200℃,with the increase of temperature,the grain gradually becomes coarser,but the recovery and recrystallization occurs at 250℃,and the grain becomes smaller.The grain is elongated at different temperatures,but the grain has obvious directionality,the grain orientation is different and the sliding mode is different.With the increase of temperature and precipitation on the pile up of dislocations in the interface,the dislocation density increases obviously after stretching,tensile deformation promotes proliferation of dislocations.