激光增材制造技术发展及在航天领域的应用进展

Development of Laser Additive Manufacturing Technology and Its Application Progress in Aerospace Field

增材制造(AM)技术作为近30多年来发展起来的新型数字化制造技术,具有快速制造复杂结构产品、高效利用原材料、可高度优化产品结构及适应个性化小批量生产等优点,非常契合航天装备日益整体化、复杂化、轻量化、结构功能一体化制造需求,为传统航天制造业的转型升级提供了巨大契机。近年来,以金属粉末为原材料、以激光为热源的激光增材制造(LAM)技术已成为AM技术领域最为热门的研究方向之一,其在航天领域的应用范围已从零部件级逐渐发展至整机级,且正在迈向工业化和智能化。本文针对航天领域广泛应用的3类典型轻质高强金属材料(铝合金、钛合金及镍基高温合金)、3类典型结构(大型整体结构、异种金属结构、发动机整机结构),介绍了近年来国内外LAM技术的发展及在航天领域的应用进展,分析了当前存在的问题和不足,并对未来LAM技术潜在研究发展方向进行了展望。

As a new digital manufacturing technology developed in recent 30 years,additive manufacturing(AM)technology has the advantages of rapidly manufacturing complex structure products,efficiently using raw materials,highly optimizing product structure and adapting to personalized small batch production.It is very suitable for the current and future aerospace equipment manufacturing needs of increasing integration,complexity,lightweight and integration of structure and function,and provides a great opportunity for the transformation and upgrading of traditional aerospace manufacturing industry.In recent years,the laser additive manufacturing(LAM)technology with metal powder as raw material and laser as heat source has become one of the most popular research directions in the field of additive manufacturing technology.Its application range in the aerospace field has gradually developed from the part level to the whole machine level,and is moving towards industrialization and intellectualization.Based on this,aiming at three types of typical light and high-strength metal materials(i.e.,aluminum alloys,titanium alloys and Ni-based superalloys)and three types of typical structures(i.e.,large integral structure,heterogeneous metal structure and whole engine structure)widely used in the aerospace field,this paper reviewed current internal and international development situation of LAM technology in recent years and its application progress in the aerospace field,analyzed the existing problems and deficiencies and provided new prospects on the potential research and development direction of LAM technology in the future.This paper firstly summarized the research and application status and development direction of LAM of aluminum alloys,titanium alloys and Ni-based superalloys,and then reviewed the progress and challenge of LAM of three typical aerospace structures,namely large integral structure,heterogeneous metal structure and whole engine structure.Finally,the key problems to be solved in the engineering application and development of LAM technology in aerospace field in the future were pointed out and the future development direction was prospected.Aerospace industry was one of the main forces to promote the development and application of additive manufacturing technology.In this paper,the development and application progress of LAM technology of three types of typical light and high-strength metal materials in recent years had been reviewed.It could be predicted that the development trend of LAM technology was to move towards industrialization and intellectualization,and realize the integration of material,structure,process,performance/function.In order to accelerate the industrialization and intellectualization development of additive manufacturing and support the construction of China’s aerospace power,the authors suggested that there were still the following key problems to be studied and solved in the engineering application and development of LAM technology in the aerospace field.Firstly,due to the lack of time for the research and development of additive manufacturing technology,the research on design,materials and processes was not deep enough,and mature and reliable design methods,rich material systems,detailed process database and efficient post-processing technologies were lacking,and these were not enough to support the rapid industrial application and development needs of additive manufacturing in aerospace field.The technical research for the whole process of additive manufacturing needed to be further strengthened.Secondly,at present,the research and application of LAM technology were still focused on the traditional alloys.The traditional alloys composition designed based on the equilibrium solidification process theory was difficult to meet the non-equilibrium physical metallurgy characteristics of LAM,which led to the common problems of LAM,such as high crack sensitivity,poor toughness and fatigue performance,and serious anisotropy.Thus,it was urgent to improve the material design theory,develop and establish a special material system library based on the characteristics of LAM.Thirdly,there was a lack of technical means for the design,preparation and forming of multiphase materials/multi-materials,multi-scale innovative structures,and this put forward revolutionary requirements for the equipment and process of AM.Thus,the research and development of innovative AM technologies and equipment such as multi-material printing,macro/micro multi-scale structure printing,multi-process integration and coordination printing must be accelerated.Fourthly,there was a lack of simulation and monitoring technology and method of LAM process for the whole process of full-scale component level forming.On the one hand,at present,the calculation equivalent of the numerical simulation physical model of AM was generally at the weld bead level.It was urgent to develop a cross-scale multi physical field numerical simulation algorithm and calculation model for the full-scale component level forming process that took into account the calculation efficiency and accuracy.On the other hand,at this stage,the intelligent degree of AM equipment was not high.There were many problems,such as less feedback information from the monitoring system,unable to optimize the process parameters in real time,and low maturity of intelligent diagnosis and processing.Thus,it was urgent to develop an intelligent AM system and equipment integrating synchronous on-line monitoring of multiple metallurgical features and intelligent fault diagnosis and processing.Finally,at present,LAM technology in the aerospace field was in rapid development,but the development of the supporting technical standards was relatively lagging behind,and the construction of the standard system could not keep up with the development of engineering applications,which seriously restricts the technical standardization and industrial development.There was an urgent need to form perfect specifications and standards for the detection and evaluation of special materials,processes,equipment and products.