Visualized simulation and observational study on core/shell structure in immiscible alloy powders
LI Mei1，2，SHI Shengqi1，QIN Lixia1，PENG Yinli1，2，ZHOU Xianhui1
（1. School of Intelligent Manufacturing, Nanyang Institute of Technology, Nanyang 473004, China; 2.Engineering
Research Center of Additive Manufacturing Aeronautical Materials of Henan Province, Nanyang 473004, China）
Abstract：An annular temperature gradient field was established by a self-made hot stage, and in-situ observa‐
tion on the phase separation using SCN-H2O solution was performed to“simulate”the evolutionary procedure
of the core/shell structure forming in immiscible alloy powders under microgravity conditions. The results show
that the size of the second phase (L2) microspheres keeps changing during the migration to the specimen center.
Firstly, the initial L2 phase becomes larger in the two-phase region due to collisions, but it is not obvious. Sec‐
ondly, the size decreases after L2 phases exceed the binodal-temperature position and enter the single-phase re‐
gion. Finally, with the decreasing temperature of specimen, the size of L2 phase increases rapidly due to fierce
collisions and forms a core structure. In addition, the core structure is formed by the L2 phase microspheres ex‐
periencing multiple collisions in the center of the specimen.
2023, Vol. 33 
