新型Cu-Cr-Zr-Co-Si电阻焊电极合金组织与性能研究

发布时间：2018-05-21 03:16

  本文选题：电极合金 + Cu-Cr-Zr-Co-Si合金　； 参考：《南昌航空大学》2017年硕士论文

【摘要】：本文在传统点焊电极制备工艺下,向Cu-0.8Cr-0.15Zr合金添加少量Co、Si、Y元素,以期通过多元复合强化方法提高铜铬锆点焊电极的综合性能。实验采用金相显微镜、扫描电镜、能谱分析仪、X射线衍射仪等材料研究方法,系统的研究了合金元素添加(Co、Si、Y)、合金元素含量(Co、Si)、合金元素比例(Co/Si)及多级时效处理对铜铬锆合金组织和性能的影响规律。主要得到以下研究结果:1.添加Co、Si、Y元素后合金晶粒细化,铸态显微组织为细小的等轴晶粒,基体内弥散分布着大量的Co5Cr3Si2相和Co、Si组成的灰色析出相,析出相有明显的偏聚。固溶处理后,灰色析出相完全溶解,但Co5Cr3Si2相并未溶解且有所长大。随固溶温度上升,合金导电率均快速下降,硬度值快速提高。2.时效阶段,晶界处及晶粒内部出现细小的析出相颗粒,随着时效时间的延长,析出相颗粒逐渐增多,且Co5Cr3Si2相逐渐粗化。时效后期,基体中未检测出Cr元素,且出现了由Co、Zr、Cr、Si元素组成的析出相。析出相主要有Co5Cr3Si2相、Co2Si相、CoZrCrSi相。导电率初期快速上升,后期上升趋势减缓保持平稳。时效温度越高,导电率达到峰值时间越短。各合金均在450℃或500℃时效时硬度达到最大值,且500℃时效后期、550℃时效中后期合金硬度快速下降。3.添加Co、Si元素后,时效态导电率下降35-40%IACS;硬度值上升30-48HV;添加稀土元素Y后,合金导电率上升2-3.5%IACS;硬度值小幅上升4-30HV;添加合金元素后,合金高温力学性能增强。抗高温软化性能明显提高,其软化温度高达686℃。4.随Co/Si元素比例增大,合金硬度、导电率大小顺序始终保持:(Co/Si=5)(Co/Si=4)(Co/Si=3)。元素比例对合金硬度峰值、导电率峰值影响较大,分别为15-40HV、6.1-18.3%IACS。随着合金中Co元素含量的增加,合金耐高温软化性能下降。5.保持Co/Si=4:1比例不变,随着Co、Si元素含量增加,合金导电率逐渐下降,硬度值提高。合金元素含量对导电率峰值的影响不大,在1-5%IACS,对合金硬度峰值影响有限,只有6-10HV。且随着合金元素添加量增多,合金耐高温软化性能下降。6.合金经200℃x2h预时效处理后,合金显微组织变化不大,导电率、硬度较固溶态均略有升高。固溶+200℃x2h预时效+时效处理后,合金组织大小均匀,晶粒有所粗化,析出相颗粒增多,合金导电率、硬度峰值分别提高3.5%IACS、8.3HV,但合金耐高温软化性能下降。
[Abstract]:In this paper, in order to improve the comprehensive properties of copper-chromium-zirconium spot welding electrode, a small amount of Co-Si-Y element was added to Cu-0.8Cr-0.15Zr alloy under the traditional spot welding electrode preparation process. The experiments were carried out by means of metallographic microscope, scanning electron microscope, energy dispersive analyzer and X-ray diffractometer. The effects of alloy elements on the microstructure and properties of copper-chromium-zirconium alloy were systematically studied. The main results are as follows: 1: 1. After the addition of Co-Si-Y element, the grain size of the alloy is fine, the as-cast microstructure is a fine equiaxed grain, a large number of Co5Cr3Si2 phases and gray precipitated phases composed of Co-Si are distributed in the base, and the precipitates have obvious segregation. After solid solution treatment, the gray precipitated phase was completely dissolved, but the Co5Cr3Si2 phase was not dissolved and grew up. With the increase of solution temperature, the conductivity and hardness of the alloy decreased rapidly. At the aging stage, fine precipitates appeared at grain boundaries and inside the grains. With the prolongation of aging time, the precipitates gradually increased and the Co5Cr3Si2 phase coarsened gradually. In the later stage of aging, no Cr element was detected in the matrix, and a precipitated phase composed of the element Co-ZrZrCr-Si was found in the matrix. The precipitated phase mainly consists of Co5Cr3Si2 phase, Co 2Si phase and CoZrCrSi phase. The conductivity increases rapidly at the beginning of the year, and keeps steady at the later stage. The higher the aging temperature, the shorter the peak time of conductivity. The hardness of each alloy reached the maximum value at 450 鈩，

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