轮轨试样Co基合金激光熔覆层组织及磨损性能

发布时间：2018-08-02 16:20

【摘要】：为提高轮轨材料的耐磨性降低轮轨磨损,利用CO2多模激光器在轮轨试样表面获得Co基合金熔覆层,测试分析了其组织结构性能和显微硬度,利用MMS-2A微机控制摩擦磨损试验机对比研究了激光熔覆处理与未处理轮轨试样的抗磨损性能.结果表明:激光熔覆处理后在轮轨试样表面获得与基体良好结合厚度约1 mm的熔覆层;熔覆层主要由枝晶(γ-Co)和共晶组织(Cr23C6+γ-Co)构成,初生相为γ-Co过饱和固溶体,富含Cr元素,共晶组织中富含Co元素;结合区为粗大柱状晶,从中部到表层出现胞状晶、树枝晶等多种形态.离界面越远组织越细密,组织生长方向紊乱;结合区存在元素扩散,尤其是Fe、Cr和Co含量变化显著;激光熔覆Co基合金后轮轨试样硬度分别提高约52.98%和43.44%,能有效降低对摩副磨损,轮轨抗磨损能力提高约为原来的5倍.
[Abstract]:In order to improve the wear resistance of wheel / rail material and reduce wheel / rail wear, Co-based alloy cladding layer was obtained by CO2 multimode laser on the surface of wheel / rail sample. The microstructure, properties and microhardness of the coating were tested and analyzed. The wear resistance of laser cladding and untreated wheel / rail specimens was studied by MMS-2A microcomputer controlled friction and wear tester. The results show that after laser cladding, a cladding layer with a thickness of about 1 mm is obtained on the surface of wheel / rail specimen, which is mainly composed of dendrite (纬 -Co) and eutectic structure (Cr23C6 纬 -Co), and the primary phase is 纬 -Co supersaturated solid solution, which is rich in Cr. The eutectic structure is rich in Co and the binding zone is a coarse columnar crystal with a variety of morphology such as cellular crystal dendrite and so on from the middle to the surface. The closer the interface is, the finer the microstructure is, the more the direction of microstructure growth is disorder, the element diffusion exists in the binding zone, especially the change of Fe Cr and Co content is remarkable, the hardness of wheel / rail specimen after laser cladding Co-based alloy increases by 52.98% and 43.44%, respectively, which can effectively reduce the wear of friction pair. The wear resistance of wheel / rail is increased by about 5 times as much as the original one.
【作者单位】：西南交通大学摩擦学研究所;
【基金】：国家自然科学基金资助项目(51174282) 四川省科技支撑计划项目(2014GZ0009-6) 教育部创新团队科学基金资助项目(IRT1178)
【分类号】：TG178

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