Gas atomization of γ‐TiAl Alloy Powder for Additive Manufacturing

Abstract

The aim is, first, to optimize gas atomization of a γ‐TiAl alloy at the laboratory scale (atomized mass < 150 g) and, second, to investigate the microstructure of the produced powders. Gas atomization variables, such as the gas pressure and the melt temperature, are adjusted to produce the highest yield of particles with sizes smaller than 150 μm. The morphology and microstructure of these powders is characterized by scanning electron microscopy, as well as electron backscattered diffraction. The fine particles of interest are found to be single α2 polycrystals with spherical shape and negligible porosity. Overall, these particles meet the morphological requirements of raw powders for additive manufacturing powder‐based methods, provided the small loss of Al that takes place during melting is compensated by increasing the amount of this component in the starting alloy.

Novel Cold Crucible Ultrasonic Atomization Powder Production Method for 3D Printing

“…Depending on the material, the total available yield for AM (particles less than 100 µm in diameter) reached 63.5% for the Au-based alloy. Such efficiency is comparable to laboratory-scale gas atomizers [ 6 ]. The coarsest particles were obtained in the case of the AMZ4 + W alloy; only 13.5% (11.8 + 1.7) were obtained below 100 μm, which is attributed to the increased viscosity of the tungsten alloyed melt [ 27 ].…”

“…Typically, such powders are produced via gas atomization [ 3 ]; although, due to the industrial scale of atomizers, the search for new alloys fine-tuned for AM is expensive and limits the number of compositions able to be tested [ 4 ]. Such limitation is particularly troublesome during chemical optimization of precious metal powders such as gold [ 5 ] and highly reactive [ 6 ] or radioactive materials [ 7 ]. The main limitation of gas and centrifugal atomization is associated with the high speed of pulverized particles during the atomization process, which requires a large sized atomization tower [ 8 , 9 ].…”

Spark Plasma Sintering of Titanium Aluminides: A Progress Review on Processing, Structure-Property Relations, Alloy Development and Challenges

“…The current preferred method for mass production of metallic powders consolidated using various methods including SPS is GA [20,21]. Although GA is said [21] to be more costly compared to water atomization, improved yields of spherical powders are achieved aiding flowability. The conventional basic operation of gas atomisation (GA) is illustrated in Figure 1.…”

“…The solidified metal droplets are then accumulated at the powder container for collection. According to Martín et al [21], processing parameters such as the melt temperature and flow, nozzle type and gas purity and pressure affect the powder size and quality. The production of γ-TiAl powders using GA is rather challenging.…”

Effects of Solidification Rates on Microstructure Refinement and Elemental Distribution of Ti44Al6Nb1.0Cr2.0V0.1B0.15Y Alloy by Rapid Solidification

“…TiAl-based intermetallic alloys are promising high-temperature structural materials considered as a potential replacement for the existing Ni-based alloys in the aerospace and automotive industries because of their low density, high strength and stiffness, and good creep resistance at elevated temperatures. [1][2][3][4] The γ-TiAl intermetallics are used in low-pressure turbine blades in the engines of the Boeing 787 and Boeing 747-8 aircraft, which has created interest in the development of TiAl-based alloys. [5][6][7] Issues such as low ductility and fracture toughness at room temperature also need to be resolved.…”