激光熔覆具有能量密度高、对工件热效应小、熔覆层与基体冶金结合、熔覆层组

Laser cladding has the advantages of high energy density, small thermal effect on the workpiece, metallurgical combination of the cladding layer and the substrate, dense organization of the cladding layer, and obtaining an alloy cladding layer with better surface properties. Therefore, laser cladding has gradually become one of the methods for surface modification of copper and its alloys. Although laser cladding has achieved certain achievements and economic benefits in copper surface modification, it is still difficult to prepare high-quality, high-performance functional cladding layers. The main problem is the physical and chemical properties of copper itself. <br>(1) For the coating material, due to the poor wettability between copper and various materials, and the interface bonding strength is weak, it is necessary to study more coating material systems and optimize the composition of the coating powder to ensure the coating and substrate To achieve defect-free metallurgical integration. <br>(2) In terms of preparation process, copper has a very high reflectivity to the laser. The use of composite surface treatment technology can improve the laser absorption rate. Increasing the thickness of the coating will increase the probability of crack occurrence 3 |. The quality of the coating cannot be guaranteed. Therefore, it is necessary to explore the cladding process with flexible operation and low processing cost, further optimize the process parameters, and minimize the energy loss provided by the laser on the premise of ensuring the quality of the cladding layer. In addition, the addition of rare earth elements and nanomaterials can refine the crystal grains of the cladding layer and help reduce cracks. <br>(3) Regarding the microstructure and performance of the coating, the current research only focuses on the mechanical properties of the copper surface, and there are few studies on the effect of the coating on the conductivity. The mechanism of the effect of laser cladding technology on copper conductivity is also difficult to explain clearly. In the future, the surface modification of copper will develop towards the comprehensive performance of wear resistance, corrosion resistance, high temperature resistance, good thermal conductivity and electrical conductivity. In addition, the wear resistance, corrosion resistance and conductive mechanism of the cladding layer need further study.

激光熔覆具有能量密度高、对工件热效应小、熔覆层与基体冶金结合、熔覆层组织致密、获得表面性能较好的合金熔覆层等优点。因此，激光熔覆逐渐成为铜及其合金表面改性的手段之一。尽管激光熔覆在铜表面改性方面取得了一定的成就和经济效益，但仍难以制备出高质量、高性能的功能性熔覆层。主要问题是铜本身的物理和化学性质。<br>(1)对于覆层材料，由于铜与多种材料之间的润湿性差，界面结合强度弱，有必要研究更多的覆层材料体系，优化覆层粉末的组成，以确保覆层与基体实现无缺陷冶金结合。<br>(2)在制备工艺方面，铜对激光有极高的反射率。采用复合表面处理技术可以提高对激光的吸收率。涂层厚度的增加将增加裂纹发生的概率3|。涂层质量无法保证。因此，有必要探索操作灵活、加工成本低的熔覆工艺，进一步优化工艺参数，在保证熔覆层质量的前提下，最大限度地减少激光提供的能量损失。此外，稀土元素和纳米材料的加入可以细化熔覆层的晶粒，有助于减少裂纹。<br>(3)关于镀层的微观结构和性能，目前的研究仅集中在铜表面的力学性能上，而关于镀层对电导率影响的研究较少。激光熔覆技术对铜导电性影响的机理也难以解释清楚。未来，铜的表面改性将向耐磨、耐腐蚀、耐高温、良好的导热性和导电性的综合性能发展。此外，熔覆层的耐磨性、抗腐蚀机理和导电机理还需要进一步研究。

Laser cladding has the advantages of high energy density, small thermal effect on workpiece, metallurgical combination of cladding layer and matrix, compact structure of cladding layer and good surface performance of alloy cladding layer. Therefore, laser cladding has gradually become one of the means of surface modification of copper and its alloys. Although laser cladding has made some achievements and economic benefits in surface modification of copper, it is still difficult to prepare functional cladding layer with high quality and performance. The main problem is the physical and chemical properties of copper itself.<br>(1) For the cladding materials, because of the poor wettability between copper and various materials and the weak interface bonding strength, it is necessary to study more cladding material systems and optimize the composition of the coating powder to ensure that the cladding and the substrate can achieve flawless metallurgical bonding.<br>(2) In the preparation process, copper has high reflectivity to laser. The absorption rate of laser can be improved by using composite surface treatment technology. The increase of coating thickness will increase the probability of crack occurrence. Coating quality cannot be guaranteed. Therefore, it is necessary to explore the cladding process with flexible operation and low processing cost, further optimize the process parameters, and minimize the energy loss provided by laser on the premise of ensuring the quality of cladding layer. In addition, the addition of rare earth elements and nano materials can refine the grains of the cladding layer and help to reduce cracks.<br>(3) As for the microstructure and properties of the coating, the current research only focuses on the mechanical properties of the copper surface, while the research on the effect of the coating on the conductivity is less. The mechanism of the influence of laser cladding on the conductivity of copper is also difficult to explain. In the future, the surface modification of copper will develop to the comprehensive properties of wear resistance, corrosion resistance, high temperature resistance, good thermal conductivity and conductivity. In addition, the wear resistance, corrosion resistance mechanism and conductive mechanism of the cladding layer need further study.<br>