The Role of Electric Current-Associated Free Energy and Forced Convection on Grain Refinement in Pure Aluminum under Electropulsing

Materials

Hui Xing¹  Pengfei Yin²  Kaikai Song³  Limin Zhang⁴  Rong Zhang⁴  Ning Li⁴  Hongjing Wu⁴ 

[1] Information Engineering, Shandong University (Weihai), 180 Wenhua Xilu, Weihai 264209, China;College of Science, Sichuan Agricultural University, Ya’an 625014, China;;School of Mechanical, Electrical &Shaanxi Key Laboratory of Condensed Matter Structures and Properties and Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072, China;

关键词: alternating electropulsing;    pure aluminum;    solidification;    fine equiaxed grains;   

DOI  :  10.3390/ma12233846

来源: DOAJ

【 摘 要 】

An experimental study with respect to the effect of an alternating electropulsing on grain refinement in pure aluminum was reported. The macrostructural observation with the mold preheated to different temperature and embedded the metal mesh indicated that the change of electric current-associated free energy related with the position of crystal nuclei (ΔG_em) and forced convection dominated the generation of fine equiaxed grains (FEG). Under electropulsing with 480 A, ΔG_em induced the dissociation of crystal nuclei from the upper interface of the electrode and the melt, leading to the generation of FEG. For a larger current intensity, FEG originated from the dissociation of crystal nuclei on the side wall besides the upper interface due to ΔG_em and the forced convection. Furthermore, the model coupling the dissociation of crystal nuclei and dendrite fragmentation due to the forced convection and the dissociation of crystal nuclei due to ΔG_em was presented to explain the formation mechanism of FEG in pure aluminum under electropulsing.

【 授权许可】

Unknown