In March 2020, HEHT Titanium Alloy Materials Technology Group, a subsidiary of China Aerospace Materials Research Institute, which specializes in high-end titanium alloy technology, completed the development of TA32 high-temperature titanium alloy powder and laser selection melting forming (SLM) parameter optimization of TA32 powder, which means China's high-temperature titanium alloy additive manufacturing technology has new developments.
In recent years, with the rapid development of the aerospace industry, especially the development of aero engines and hypersonic vehicles, the demand for titanium alloy materials has also increased dramatically. In order to further reduce weight and increase the thrust-to-weight ratio of aircraft, titanium alloys are increasingly used in aircraft engine compressor wheels, blades, integral blade disks, casings and rotors, as well as missile rudder wing skeletons, cabins and engine inlets. Manufacturing of airway and other parts. The continuous improvement of the performance of aerospace vehicles has put forward higher requirements for the use temperature of titanium alloys, and the development of high-temperature titanium alloys is imminent.
TA32 titanium alloy, whose nominal composition is Ti-5.5Al-3.5Sn-3Zr-1Mo-0.5Nb-0.7Ta-0.3Si, is a new type of near-alpha titanium alloy newly developed in China. It still has good creep and long-lasting properties, and is expected to replace some steel or nickel-based superalloy materials. The short-term service temperature can reach 600 ℃, and it has good comprehensive mechanical properties such as tensile, fatigue and creep. HEHT systematically carried out research work on powder preparation technology and laser selective melting forming technology for TA32 titanium alloy.
Development of Additive Manufacturing TA32 Titanium Alloy Powder
HEHT adopts water-cooled copper crucible vacuum induction melting gas atomization powdering technology to complete the development of TA32 titanium alloy powder. The principle is to use electromagnetic induction heating to achieve the smelting of titanium alloy rods in water-cooled copper crucible. It enters the diversion pipe to form a stable and fine liquid flow. When the alloy liquid flow flows through the nozzle through the atomizing nozzle, it is crushed and solidified by the high-speed air flow generated by the atomizing nozzle to form fine powder particles. High yield and other advantages.
After testing, the TA32 titanium alloy powder produced by this technology has excellent properties such as high purity, high sphericity, high fluidity, and high bulk density. Various performance tests were carried out on the TA32 with a particle size range of 15-53μm. The oxygen content of the powder was 1000ppm, the nitrogen content was 190ppm, and the hydrogen content was 50ppm. The content of various impurity elements was far below the relevant requirements of the GB / T3620.1-2016 standard. The physical properties of the powder were tested. The median particle size d50 of TA32 powder was 36 μm, the bulk density was 2.4 g / cm3, and the Hall flow rate was 45 s / 50 g. The various performance indicators met the metal 3D printing process requirements.
TA32 titanium alloy powder laser selective melting and forming performance
By controlling the laser energy density, TA32 titanium alloy powder was subjected to laser selective melting 3D printing forming test under different process parameters. The metallographic test results showed that the grain size of the TA32 powder laser selective melting forming specimen was relatively small, without obvious cracks, Defects such as holes. Further test the mechanical properties of the test piece, the results show that the tensile strength and elongation of the sample at room temperature reached 1200MPa and 8%. The test pieces have high-temperature tensile strengths of 867 MPa, 819 MPa, and 712 MPa at 500 ° C, 550 ° C, and 600 ° C; plastic values of 14.4%, 15.9%, and 17.0%, and have excellent mechanical properties.
About HEHT Titanium Alloy Materials Technology Group
HEHT Titanium Alloy Materials Technology Group covers an area of over 260,000 square meters, with a total investment of 1.355 billion yuan. It is a high-end titanium alloy industrial base integrating R & D, design, manufacturing and service. It leads China's high-end titanium alloy industry in research and development technology, product quality, production management, talent cultivation, application promotion, market cultivation, etc. It is an international first-class titanium product R & D and manufacturing base.
The product includes five business areas: titanium alloy precision casting molding, titanium alloy precision plastic molding, titanium alloy powder molding, titanium 3D printing, titanium parts and equipment integration.
High-end titanium alloy products: high-quality titanium ingots, billets with special shapes, large-caliber titanium alloy tubes, titanium wires for aerospace fasteners, and special extruded titanium alloy profiles. Meet the high-temperature, high-strength, high-stability, forging, casting, rolling, and extrusion billet requirements of aerospace, aviation, and deep sea; cater to the needs of oil and gas exploration and deep-sea transportation; titanium for the aerospace industry, especially the Chinese-made large aircraft C919 Market demand for alloy fasteners.
Relying on the advantages of military technology, the company exerts the brand effect of aerospace, takes market demand as the traction, bases on the needs of aerospace, faces the aviation, shipbuilding, civil chemical industry, sports and leisure, and biomedical markets. First-class, internationally renowned titanium industry base, leading China's high-end titanium alloy industry, driving and promoting the development of China's titanium industry.