Grain nucleation and growth behavior of a Sn-Pb alloy affected by direct current: An in situ investigation

Fenfen Yang¹，Zongning Chen^1,2，Fei Cao¹，Rong Fan³，Huijun Kang¹，Wanxia Huang⁴，Qingxi Yuan⁴，Tiqiao Xiao⁵，Yanan Fu⁵，Tongmin Wang¹

1. Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology2. School of Chemical Engineering, Dalian University of Technology3. School of Automotive Engineering, Dalian University of Technology4. Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences5. Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences

摘 要：In situ synchrotron X-ray radiography was used to study the effect of direct current（DC） on the grain nucleation and growth of Sn-50 wt.%Pb alloy. The results showed that applying DC adequately during solidification could effectively enhance the grain nucleation and inhibit its growth. Imaging of comparative experiments with varying DC intensity indicated that the final grain size, determined by the competition between grain nucleation and growth, was sensitively dependent on the DC intensity. It was found that the average grain size was decreased from 1632 to 567 μm with DC density of 1.5 A/mm² compared to the case without DC. Beyond this value, raising the current density may cause a significant decrease in the nucleation rate, and thus lead to a coarsening of the grain structure.

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