Zr元素对铁道机车用铜合金组织与性能的影响

Effect of Zr Element on Microstructure and Properties of Copper Alloy for Railway Locomotive

采用金相光学显微镜(OM)、扫描电子显微镜(SEM)和维氏硬度计、拉伸试验机、电导率测试仪等分析和测试手段,对比分析了Cu-Cr合金和Cu-Cr-Zr合金的显微组织、硬度、拉伸性能和导电性能等。结果表明,固溶态Cu-Cr合金和Cu-Cr-Zr合金的平均晶粒尺寸分别为198.6μm和100.3μm,添加适量Zr有助于细化铜合金的晶粒;时效态Cu-Cr-Zr合金中同时存在未溶的尺寸约1~2μm的颗粒状富Cr相和时效析出的尺寸约0.6μm的球形富Cr相;在Cu-Cr合金中添加Zr元素有助于改善富Cr相的存在形式,使得短棒状富Cr相向球形富Cr相转变,且球形富Cr相尺寸有所减小。冷轧态和时效态Cu-Cr-Zr合金的抗拉强度都分别高于冷轧态和时效态Cu-Cr合金,添加Zr元素有助于提升时效态Cu-Cr合金的强塑性和电导率,且时效处理后Cu-Cr合金和Cu-Cr-Zr合金的强塑性和电导率会进一步提升,这主要与Zr元素的添加有助于细化晶粒、改善富Cr相的存在形式和析出细小球形析出相有关。

The microstructure,hardness,tensile property and electrical conductivity of Cu-Cr alloy and Cu-Cr-Zr alloy were compared and analyzed via means of metallographic optical microscope(OM),scanning electron microscope(SEM),Vickers hardness tester,tensile testing machine and conductivity tester.The results show that the average grain size of solid solution Cu-Cr alloy and Cu-Cr-Zr alloy are 198.6μm and 100.3μm respectively,and adding proper Zr can help refine the grain of copper alloy;the grains of the aged Cu-Cr-Zr alloy with insoluble size of about 1-2μm and 0.6μm of aging precipitation are also found;adding Zr to Cu-Cr alloy can help to improve the storage of Cr-rich phase in the form,the short rod Cr-rich phase changes to the spherical Cr-rich phase,and the size of the spherical Cr-rich phase decreases.The tensile strength of cold rolled and aging Cu-Cr-Zr alloys is higher than that of cold rolled and aged Cu-Cr alloys respectively.Adding Zr can improve the strength&plasticity and conductivity of aged Cu-Cr alloy,and the strength&plasticity and conductivity of Cu-Cr alloy and Cu-Cr-Zr alloy will be further improved after aging treatment,which is mainly related to the fact that the addition of Zr helps to refine the grains,improve the existing form of Cr-rich phase and precipitate small spherical precipitates.