Crystallization of Fe-W-B Amorphous Powder Prepared by Gas Atomization

Abstract

In this work, the effects of master alloy composition and annealing temperature on the amorphization and crystallization behavior of Fe-W-B powders prepared by gas atomization using compacts of Fe, W and B powder mixture were systematically studied. The results show that only the master alloy with high content of W (19.9 at.%) and B (13.6 at.%) of the six alloys studied yielded amorphous Fe-W-B powders. The alloying elements W and B are believed to have a glass-forming ability (GFA)-enhancing effect, which together with the high cooling rate of gas atomization leads to the formation of amorphization. The difference in the average particle size of 3–10 μm for the six atomized powders indicates that the master alloys with different W and B contents have different superheat and melt viscosity at the same atomization temperature. The Fe-W-B amorphous powder is structurally stable within 600 °C and crystallizes from the edge of the particles when the temperature increases to 700 °C, and its crystalline precipitates include α-Fe, FeWB and Fe7W6. The nuclear shielding tests and Monte Carlo N Particle Transport Code (MCNP) calculated results revealed that the Fe-W-B amorphous powder has a much better shielding performance for γ-rays and neutrons than that of iron. This work provides an efficient strategy for fabricating Fe-W-B amorphous powder with promising nuclear shielding potential and sheds light on the crystallization behaviors of this alloy.