铜铬合金具有导电性好、导热性好、强度硬度高、抗腐蚀性强等特点，被广泛应用于电力及相关行业，例如高压电网、集成电路、电器元件等。随着高压电网的升级，传统方法制备的铜铬合金难以满足高电压、大电流下的电路开断要求，铜铬合金表层较大颗粒的铬被烧蚀击穿为主要失效原因。

激光表面改性技术可在材料表层实现快速熔凝以细化晶粒，大幅提升铜铬合金的电学及力学性能。目前的研究主要侧重于材料级的激光熔凝改性实验及基于有损检测的改性层性能研究，对于铜铬合金触头等结构件的表面熔凝改性工艺还不成熟。改性层的破坏性测试无法满足对结构件改性层的测试需求。缺乏有效的无损检测方法，难以在不破坏结构的情况下建立改性工艺和改性层性能之间的关联，成为制约铜铬合金激光熔凝改性技术在工业应用中的瓶颈问题。因此探索快速无损检测方法，建立激光工艺参数与改性层特征的关联，从而优化铜铬合金触头结构件表面改性工艺，是突破以上瓶颈问题的关键。本文结合高压输电行业对铜铬合金改性的重大需求和国内外研究现状，针对铜铬合金触头表面的激光熔凝技术，开展了以下研究工作。

1. 对激光表面改性试验平台进行部分升级改造。通过对设备调试升级实现了多个结构件并行改性，提升实验效率。建立了试样形貌实时采集系统，为后续无损检测研究提供实验基础。

2. 研究了改性层表面形貌与工艺参数的关系，探索表面形貌随激光能量输入的演化规律。依据不同的能量输入和改性后试样的表面形貌特征，对改性层进行分类，是通过无损检测建立改性层性能和工艺参数之间的关联的重要支撑。

3. 以表面形貌图像为基础提出了一种基于机器视觉的检测方法。采用一种改进的二值化方法从该背景图像中准确分割视觉显著区域，再基于几何矩提取具有空间变换不变性的连通域形状特征，最后结合支持向量机等分类算法检测试样的表面改性质量。

4. 基于以上研究工作，以无损检测结果为基础，对铜铬合金触头表面激光熔凝改性的工艺优化进行了探索性研究。

Copper-chromium alloy has the characteristics of good electrical conductivity, good thermal conductivity, high strength and hardness, and strong corrosion resistance, which is widely used in electricity and related industries, such as high-voltage power grids, integrated circuits and electrical components. With the upgrading of high-voltage power grids, the material prepared by traditional methods cannot meet the circuit breaking requirements under high voltage and large current. The ablation and breakdown of the larger particles of chromium on the surface of the CuCr alloy is the main cause of failure.

Laser surface modification technology achieves grain refinement by rapid remelting of the surface material and greatly improves the electrical and mechanical properties of copper-chromium alloy materials. Current research mainly focuses on the laser remelting modification experiment of material samples and the performance of the modified layer tested by the damage detection. The surface remelting modification process of structural parts such as copper-chromium alloy contacts is not mature. As a structural component, it is not proper to conduct destructive tests of the modified layer, thus, the effective non-destructive testing is urgently in need. It is difficult to establish the relationship between the modified process and the modified layer performance without destroying the structure, which becomes the bottleneck problem restricting the CuCr alloy laser melting modification technology in industrial applications. Therefore, exploring rapid non-destructive testing methods, establishing the correlation between laser processing parameters and modified layer characteristics, and optimizing the CuCr alloy surface modification processing parameters are key to breaking through the difficult issues. In this paper, combined with the major demand for copper-chromium alloy modification in the high-voltage power transmission industry and the current research status, the following four aspects are carried out for the laser melting technology of the copper-chromium alloy contact surface:

1. The experimental platform is partially upgraded. The equipment debugging and upgrading realized the parallel modification of multiple structural parts to improve the experimental efficiency; a real-time acquisition system for sample morphology was established to provide the basis for subsequent non-destructive testing research.

2. The relationship between the modified surface morphology and process parameters is studied, and the evolution of the surface morphology with the laser energy input is explored. According to different energy input and the surface morphology characteristics of the modified sample, the modified layer is classified, which is an important support to establish the correlation between the performance of the modified layer and the processing parameters through non-destructive testing.

3. According to the surface topography image, a detection method based on machine vision is proposed. Firstly, an improved binarization method is used to accurately segment the visually significant areas from the background image. Then, the connectivity domain shape features with spatial transformation invariability are extracted based on the geometric moment. Finally, the surface modification quality of the specimen is detected by combining support vector machines with other classification algorithms.

4. The process optimization of the surface modification of copper-chromium alloy contact by laser melting was exploratorily studied based on the above research and the results of non-destructive testing.

The research results in this article provide support for the optimization of the laser surface melting modification process of copper-chromium alloy contact structure and the industrial application and promotion of this technology. At the same time, this method of establishing the correlation between process and performance through non-destructive testing is also applicable for surface modification of other structural parts and their industrial applications.