Solidification Characterization of K418 Alloy Powders Fabricated by Argon Gas Atomization

摘要

The solidification characterization of K418 alloy powders prepared by argon atomization was studied, and thermal parameters of the alloy powder during solidification process were calculated. The results show that powder morphology is spherical shape, the average diameter of the powder is 55μm, the amount of less 100μm powder is about 90 percent, the solidification microstructure of powders particle surface are dentrite and cellular structure. Decreasing the particle size, the microstructures of particle interior change from dentrite in major to cellular structures, and the structure is more uniformed. The length of secondary dentritic arm and the cooling rate as a function of K418 alloy powders size is established, the cooling rate increases with a decrease of the powder particle size, the cooling rate is in the range of 10~(4K).S~(-1)-10~6K.S~(-1).