激光3D打印用TC21钛合金粉末制备及其成形性研究

Study on Preparation and Formability of TC21 Titanium Alloy Powder for Laser 3D Printing

采用电极感应熔炼气雾化法制备激光3D打印用TC21钛合金粉末,并利用制备的合金粉末打印出钛合金样品。采用光学显微镜、扫描电镜、X射线衍射对电极感应熔炼气雾化法制备的TC21钛合金粉末的形貌、粒径、组织进行了研究。并对成形合金的力学性能进行了分析。结果表明:在优化后的制粉工艺参数下,制备的TC21粉末为球形,粉末表面和内部都是由等轴状的原始β晶粒构成,二次枝晶沿着晶界向晶粒内部发展,主要相由α'相、β相以及金属间化合物AlTi_3、Ti_2AlNb、Zr_3Al构成。在优化后的激光3D打印参数下,打印的TC21钛合金组织为α'相、β相,以及金属间化合物AlTi_3、Ti_2AlNb、Zr_3Al。合金的金相组织分为明区、过渡区、暗区三个区域。明区为α'马氏体针,暗区为网篮组织;明区硬度达541 HV,暗区硬度达470 HV;打印合金的抗拉强度为1150 MPa,伸长率约为8%。该方法制备的TC21钛合金粉末具有良好的激光3D打印成形性。

TC21 titanium alloy powders were prepared by electrode induction melting gas atomization（EIGA）, which was used for laser 3D printing, and TC21 titanium samples were printed with the prepared powders. The morphology, particle size, microstructure of the TC21 powders were studied by optical microscopy （OM）, scanning electronic microscopy （SEM）, and X-ray diffraction （XRD）. The mechanical properties of the formed alloy were studied. The results show that TC21 powder prepared by the optimized process parameters is spherical, and the surface and interior of the powder are composed of original 13 grains,the secondary dendrite grows along the grain boundary to the grain interior. The main phases are et＇ and 13 and intermetallies of A1Ti3,Ti2A1Nb and ZrrA1. Under the improved laser 3D pringting parameters, the microstructure of the printed TC21 titanium alloy consist of the phase of a＇, 13 and intermetallics of A1Ti3,Ti2A1Nb and Zr3A1. The microstmcture of the alloy can be divided into three parts, namely light area, transitional area and dark area. a＇ martensite appears in light area, while basketweave structure appears in dark area. The microhardness of light area is 541HV and the dark area is 470 HV. The tensile strength of the printed alloy can reach 1150 MPa and the elongation is about 8%. TC21 titanium alloy powder prepared by the above method has good laser 3D printing formability.