On May 11, 2021, Xi`an Zhirong Metal Printing System Co., Ltd. (Xi’an Zhirong) announced that it has made breakthroughs in titanium alloy electron beam fuse additive manufacturing technology, and has mastered the realization of excellent mechanical properties, especially high fatigue The combination of high-performance printing process parameters has laid a solid foundation for the application of electron beam fuse metal additive manufacturing technology in large-scale aviation titanium alloy load-bearing structural parts.
At the end of 2020, Xi`an Zhirong used its self-developed ZcompleX3 electron beam fuse metal additive manufacturing system to form Ti-6Al-4V alloy materials and commissioned the Shenyang Institute of Metal Research, Chinese Academy of Sciences to perform X-ray flaw detection and different directions and stresses. High-cycle fatigue limit test under specific conditions, the test results show that there is no X-ray detectable defect inside the test block. After the sample is treated with HIP and the two-phase zone solid solution low-temperature aging dual heat treatment process, the X and Z directions The tensile-tension and tensile-compression high-cycle fatigue limits are higher than the Ti-6Al-4V bar technical standard requirements, and the data consistency is excellent.
Electron beam fuse additive manufacturing (EBAM) technology
Electron beam fuse additive manufacturing (EBAM) is a cutting-edge technology in the field of 3D printing that uses electron beam as a heat source. Only a few companies such as Sciaky in the United States and Xi'an Zhimelt in China can provide commercial products in the world.
The technical principle is as follows: In a vacuum environment, a high-energy density electron beam bombards the metal surface to form a molten pool. The metal wire is fed into the molten pool through a wire feeder and melted. At the same time, the molten pool moves according to a pre-planned path. The layers solidify and accumulate to form a dense metallurgical bond, until metal parts or blanks are manufactured.
The characteristics of this technology are very obvious, printing in a vacuum environment, effectively avoiding the mixing of impurity elements; fast forming speed, high material utilization, stainless steel fuse efficiency up to 15kg/h, suitable for rapid manufacturing of large structural parts; consistent forming process Good; it can be used for additive manufacturing of functionally graded materials (FGM) and metal matrix composites, and it can also process refractory metals such as tungsten, molybdenum, niobium, and tantalum. However, the surface accuracy of the parts is not high, and CNC processing is required in the later stage.
Titanium alloy 3D printing is a powerful weapon in the aerospace field
In aviation manufacturing, foreign titanium alloy electron beam fuse additive manufacturing technology has been successfully applied, such as Lockheed Martin’s F35 stealth aircraft flaperon spar, vertical tail rear spar, and upper wing on Airbus aircraft. This application is not only The cost is saved and the delivery time is greatly improved. The corresponding domestic applications are still in a blank state. According to Antarctic Bear, Sciaky used electron beam additive manufacturing (EBAM) technology to print more than 12,000 pounds (5443 kilograms) of titanium in 2020.
Titanium is an important structural metal developed in the 1950s. Titanium alloy is widely used in various fields because of its high strength, good corrosion resistance and high heat resistance. For example, the amount of titanium alloy in military aircraft It can reach 20% to 25% of the weight of the aircraft structure, and the amount used in aero engines generally accounts for 20% to 30% of the total weight of the structure. The first practical titanium alloy was Ti-6Al-4V, which was successfully developed by the United States in 1954. It is the ace alloy in the titanium alloy industry. Many other titanium alloys can be considered as a modification, and the amount of this alloy has accounted for all titanium alloys. 75% to 85% of the total.
The traditional processing method of titanium alloy is difficult to process, the processing cycle is long, and the material utilization rate is low. Some large structures also have complex shapes or special specifications, which are difficult to achieve by forging methods. According to statistics, the material utilization rate of China's large-scale aviation titanium alloy parts is very low, not exceeding 10% on average. Die forging and casting also require a large number of tooling and molds, which leads to an increase in development costs. By using metal additive manufacturing technology to produce titanium alloy parts, the structure can be integrated, cost and cycle can be reduced, and rapid response, moldless integrated manufacturing can be achieved, which can save more than two-thirds of materials and reduce CNC machining time by more than half , No mold is needed, and the development cost can be greatly reduced, especially for the first piece and small batch.