Solidification of A356 Alloy Under Different Directions and Magnitudes of Static Electrical Field

Abstract

A356 alloy, which is a commercial Al–Mg–Si alloy, was solidified with different magnitudes (0.42–1.25 kV cm−1) and directions of static electrical fields (E+: positive and E−: negative) to study the influences of E+ and E− on irregular interflake structure and mechanical property of Al–Mg–Si alloy. The direction of E is parallel or antiparallel to the solid–liquid (S–L) interface growth direction. The secondary dendrite arm spacing (λ2), Alα average grain surface area (Sα), sphericity ratio of Si into matrix (fSi) and Brinell hardness (HB) were measured for A356 alloy solidified with different E+ and E− values. The static electrical field force (F) affects the atomic mass flux at the S–L interface during the solidification and thus the microstructure, and physical and mechanical properties of the material are changed with E+ and E−. While the values of λ2, Sα and fSi increase with increasing the value of E−, the HB value decreases with increasing E−. However, the values of λ2, Sα and fSi decrease with increasing the E+ and the HB value increases with increasing E+. The relationships between them were determined with linear regression analysis. Graphic abstract: Optical images of microstructure for the A356 alloy solidified with different directions and magnitudes of static electric fields; (a) 0.0 kV cm−1 (b) 1.25 kV cm−1 (c) − 1.25 kV cm−1.[Figure not available: see fulltext.] © 2021, American Foundry Society.