增材制造铜/钢双金属材料研究进展

Research Progress of Copper/Steel Bimetallic Materials for Additive Manufacturing

铜/钢双金属材料具有力学强度高、物理化学性能优良等优势,在交通运输、电力能源和建筑工业等领域应用前景广阔。然而,传统熔铸工艺在制造铜/钢双金属材料时,容易在铜/钢界面处产生偏析现象,在一定程度上限制了铜/钢双金属材料的发展。与传统工艺相比,增材制造技术不仅能实现复杂加工零件的快速制造,而且在成形过程中较短的保温时间能缓和或消除异种金属材料界面产生的冶金缺陷,进而增强铜/钢双金属材料的力学性能。由于双金属材料是近年来的研究热点,有关增材制造铜/钢双金属材料的综述性文章较少,故综述了近年来激光、电子束及电弧增材制造技术制造铜/钢双金属材料的研究发展现状,分析了各技术的优缺点,并从制备方法、工艺参数及界面合金元素等角度,分析了影响材料界面组织性能变化的关键因素。发现在增材制造铜/钢双金属材料方面,目前激光增材制造技术主要应用于精度要求较高的小尺寸零部件,电子束增材制造技术适用于某些具有特殊性能的合金,如钛合金,而电弧增材制造技术适用于精度要求较低的大型复杂零部件。在铜/钢双金属材料增材制造过程中,界面处易形成显微组织分布不均匀、界面晶粒尺寸差异较大等现象,导致界面处产生应力集中,从而造成材料断裂失效。为解决上述难题,学者们已深入研究第二相形成机理,并采用优化界面处Cu-Fe比例和控制脆相金属间化合物等方式提高铜/钢双金属材料的性能。最后,对目前增材制造铜/钢双金属材料的研究发展现状进行了总结与展望,未来在冶金学和热力学方向上对铜/钢双金属材料仍需进行系统性理论研究,对双金属材料而言需要建立相关模拟数据库,以期为相关从业人员提供精细化指导建议。新型增材制造技术或复合增材制造技术的开发与应用都将成为未来增材制造铜/钢双金属材料研究的重点发展方向。

Copper/steel bimetallic materials have the advantages of high mechanical strength,excellent physical and chemical properties,and have broad application prospects in the fields of transportation,power energy and construction industry.However,when the traditional melting casting process is used to manufacture copper/steel bimetallic materials,it is easy to produce the segregation phenomenon at the copper/steel interface,which limits the development of copper/steel bimetallic materials to a certain extent.Compared with the traditional process,additive manufacturing technology can not only realize the rapid manufacturing of complex machined parts,but also shorten the holding time during the forming process,which can alleviate or eliminate the metallurgical defects generated by the interface of dissimilar metal materials,thus enhancing the mechanical properties of copper/steel bimetallic materials.As bimetallic materials have been the focus of research in recent years,there are few review articles on the additive manufacturing of copper/steel bimetallic materials.Therefore,the research and development status of copper/steel bimetallic materials produced by laser,electron beam and wire and arc additive manufacturing technologies in recent years were reviewed,and the advantages and disadvantages of each technology were analyzed.The key factors affecting the change of material interface microstructure and properties were analyzed from the aspects of preparation method,process parameters and interface alloying elements.It was found that in the additive manufacturing of copper/steel bimetallic materials,the laser additive manufacturing technology was mainly applied to small-size parts with high precision requirements,the electron beam additive manufacturing technology was applicable to certain alloys with special properties,such as titanium alloy,and the wire and arc additive manufacturing technology was suitable for large and complex parts with low precision requirements.Moreover,during the additive manufacturing process of copper/steel bimetallic materials,uneven microstructure distribution and large difference in interfacial grain size were easy to be formed at the interface,which led to stress concentration at the interface,thus causing the material to fracture and fail.In order to solve the above problems,scholars have studied the formation mechanism of the second phase in depth,and the properties of copper/steel bimetallic materials have been improved by optimizing the Cu-Fe ratio at the interface and controlling the brittle-phase intermetallic compounds.Finally,the current research and development status of additive manufacturing of copper/steel bimetallic materials are summarized and prospected.In the future,systematic theoretical research on copper/steel bimetallic materials in the direction of metallurgy and thermodynamics is still needed,and relevant bimetallic materials simulation database needs to be established in order to provide detailed guidance and suggestions for relevant practitioners.The development and application of the new additive manufacturing technology or the composite additive manufacturing technology will become the key development direction of copper/steel bimetallic materials for additive manufacturing in the future.