Characteristics of 7055A1 alloy powders manufactured by gas-solid two-phase atomization: A comparison with gas atomization process

In this paper, the principle of gas-solid two-phase atomization methodology for metal powder is demonstrated. A cost-effective production technology for high-quality metal powder was proposed. The morphology. size distri-bution. microstructure and cooling rate of two-phase atomized 7055A1 powder were examined. The experimental results have demonstrated a number of advantages and unique features of gas-solid two-phase atomization in the preparation of metal powders. When the Argon gas pressure P = 0.6 MPa and iron particle feed rate AV = 235.6 gmin. the mass median diameter (d(50)) of the 7055A1 powder manufactured by two-phase atomization process was 22.8 mu m, which is reduced by 52.7% compared with gas atomized powders with d(50) = 48.2 pm under the same atomization parameters. Experimental results also showed that the gas-solid two-phase atomized powders exhibited more Irregular shapes than gas atomized powders. The cooling rate of most powders was in the range of 10 (4)- 10 (5) K/s, and for some extra checked fine powders the cooling rate can even reach 106 K/s. The two-phase atomized powders had larger cooling rate and presented obvious rapid solidification characteristics than gas atomized powder with the same diameter. Moreover, this study indicates that gas-solid two-phase at-omization could be a promising high-quality and low-cost metal powder preparation technology.