Research On Surface Functional Structure And Properties Of Cu-based Nanocomposite Particles By Selective Laser Melting

Nowadays,with the development of industrial level and science and technology,it is known that the general performance of existing materials have been unable to meet the needs of social development,and the research and development of new materials has a long period and cost is higher.Therefore,different methods are used of the preparation of the functional structure on the surface of commom materials,and it has become a hot topic in current methods to improve the performance of materials.While keeping the performance of the substrate unchanged,the surface functional structure can also be given special functions according to the use requirements of the material.The preparation of functional coatings on the surface according to the performance of the components,not only can meet the performance requirements of the material under different conditions,but also can save costs and increase economic benefits.Abrasion resistance is one of the most common surface functional structures,which is widely used in Marine,automotive,aerospace,mining and other fields.However,its preparation methods are endless,each has its own advantages and disadvantages,and due to the technical limitations of the preparation conditions,the cost of materials with abrasion-resistant surface functional structure is relatively expensive,which limits its wide application.In this paper,the laser selective melting technology is used to prepare the functionally graded coating,which realizes the preparation of the functionally graded coating without the protection of vacuum or inert gas.It provides an important technical means for the preparation of flexible and highly stable composite surface functional structures.The main research contents of the article are as follows:Laser selective melting principle was used to simulate the preparation of the functional coating on the surface of copper-based nanocomposite particles.According to the principle of conservation of energy and momentum,the temperature field model and the fluid flow model in the molten pool were established.Through the phase change heat transfer,interfacial tension and Marangoni effect,The influence of laser parameters on the temperature gradient and fluid flow in the molten pool formed by selective laser melting was discussed.The effect of laser parameters on laser selective melting is studied by changing different laser energy,scanning speed and spot radius.The influence of the morphological quality of the formed surface coating.According to the flow characteristics of the dispersion liquid of copper nanocomposite particles,an experimental device for selective melting of the laser was built to meet the requirements of dispersion coating and laser scanning.The preparation of the dispersion of copper-based nanocomposite particles is described,the proportion of different components of dispersion is determined.Then,the laser power,scanning speed,scanning path and scanning method of the single scanning track of laser processing are compared and optimized,and the best laser processing parameters are determined.According to the selected best single-scan laser processing parameters,the laser selective melting surface coating is prepared.Firstly,a content of 10%Cu-MoS₂,Cu-SiC and Cu-Al₂O₃ composite single layer coating was prepared on 304 stainless steel plate,and compared with pure copper coating and no coating.The wear resistance of different coatings is analyzed by wear resistance test,and it is found that Cu-SiC single layer composite coating has the best wear resistance.