铝合金激光增材制造材料体系研究现状

Research Status of Laser Additive Manufacturing Material System for Aluminum Alloy

首先概述了3种激光增材制造的成形技术原理,对其成形件的主要性能进行了比较。其次重点论述了近年来铝硅系、铝铜系和铝锌系铝合金以及颗粒增强铝基复合材料4种铝合金粉末材料体系的研究发展情况。在此基础上,探讨了铝基粉末在激光增材制造应用中存在的一些难点,包括粉末流动性差、反射率和导热率高、极易氧化以及成形件产生微裂纹,介绍了解决或改善这些问题的方法和作用机制。最后归纳总结了现有铝合金在激光增材制造中仍需解决的问题,对今后的研究工作进行了展望,提出未来可以进行更多元素体系的陶瓷增强颗粒研究,并开发增强颗粒/铝基粉末智能匹配系统的展望,即能够科学选择出与激光增材制造所用铝基粉末高度匹配的增强颗粒,以及研发铝合金激光复合增材技术,以期为铝合金激光增材制造材料体系的发展研究提供有价值的参考。

Firstly,this paper briefly summarized the forming technology principles of Selective Laser Melting(SLM),Direct Metal Laser Sintering(DML)and Direct Metal Deposition(DMD),and compared the main properties and respective characteristics of their formed parts.Secondly,this paper focused on the research and development of four aluminum alloy powder material systems:Al-Si,Al-Cu,Al-Zn aluminum alloys and particle reinforced aluminum matrix composites in recent years,including their compositions and characteristics,as well as the comparison of formability and application fields of aluminum alloys of different material systems in additive manufacturing.On this basis,some difficulties in the application of aluminum based powder in laser additive manufacturing were discussed.Compared with other additive manufacturing system powder,aluminum based powder has the low density and poor spherical degree,resulting in poor powder fluidity and easy to break in powder supply in the process of laser cladding.And aluminum based powder has higher reflectivity and thermal conductivity,and need higher laser power.It is very easy to oxidize in the atmosphere or protective atmosphere that produce oxides on the surface and inside of the formed parts,and reduces the density of the formed parts,and produces micro-cracks in the formed parts due to residual stress,so as to reduce the mechanical properties of the formed parts.In view of these problems,this paper introduced and explained the causes of these difficulties,and introduced the methods and mechanism to solve or improve these problems from three aspects:improving equipment,debugging process parameters and adding reinforced granular materials.Finally,the problems that still need to be solved in the current aluminum alloy laser additive manufacturing were summarized,the future research work was prospected.It was proposed that the laser can be combined with electromagnetic field,plasma,heat treatment and other technologies to develop aluminum alloy laser composite additive technology in the future.The future research should focus on ceramic reinforced particles of more element systems and developing multi-element composite ceramic reinforced particles,explore the method of decomposing the surface and internal oxides of aluminum alloy,and carry out aluminum alloy laser additive manufacturing experiments in multiple environments such as atmosphere,room temperature and humidity,close to the actual production environments so as to promote the application in practical engineering,and develope the prospect of reinforced particles/aluminum based powder intelligent matching system,so that the reinforced particles highly matched with the aluminum based powder used in laser additive manufacturing can be scientifically selected.It is expected to provide a valuable reference for the development and research of aluminum alloy laser additive manufacturing material systems.