【摘 要】
：
Fe-48.8% Sn monotectic, Fe-40% Sn hypomonotectic and Fe-58% Sn hypermonotectic alloys have been rapidly solidified during free fall processing in drop tube. For
【机 构】
：
Laboratory of Materials Science in Space
【基金项目】
：
国家自然科学基金;陕西省自然科学基金
论文部分内容阅读
Fe-48.8% Sn monotectic, Fe-40% Sn hypomonotectic and Fe-58% Sn hypermonotectic alloys have been rapidly solidified during free fall processing in drop tube. For droplets of 100-1000 μm, the maximum undercooling for Fe-48.8% Sn, Fe40% Sn and Fe-58% Sn alloys is 270, 282 and 288 K respectively. For Fe-48.8% Sn monotectic alloy, a homogeneously dispersed microstructure can be obtained when the droplet diameter is small, and the Marangoni migration velocity Vm is 37 times as fast as Stokes velocity Vs when the dispersion sphere radius is 6 μm and undercooling is 30 K.For Fe-40% Sn hypomonotectic alloy, the microstructure undergoes a transition from columnar α-Fe dendrites distributed in Sn-rich matrix to α-Fe particles. The growth velocity of α-Fe dendrite changes from 0.45 to 4.65 m/s when the droplet diameter varies from 1000 to 100 μm. For Fe-58.8% Sn hypermonotectic alloy, the grain size of primary α-Fe dendrites decreases remarkably when undercooling increases.
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