Abstract
There is far less study of the refining effect of super gravity fields on solidification structures of metals than of the effects of electrical currents, magnetic and ultrasonic fields. Moreover, the refining mechanisms of super gravity are far from clear. This study applied a super gravity field to Al-Cu alloys to investigate its effect on refining their structures and the mechanism of interaction. The experimental results showed that the solidification structure of Al-Cu alloys can be greatly refined by a super gravity field. The major refining effect was mainly achieved when super gravity was applied at the initial solidification stage; only slight refinement could be obtained towards the end of solidification. No refinement was obtained by the super gravity treatment on pure liquid or solid stages. The effectiveness of super gravity results from its promoting the multiplication of crystal nuclei, which we call “Heavy Crystal Rain”, thereby greatly strengthening the migration of crystal nuclei within the alloy. Increasing the solute Cu content can increase nucleation density and restrict the growth of crystals, which further increases the refining effect of super gravity. Within this paper, we also discuss the motile behavior of crystals in a field of super gravity.
Highlights
In studying the effect of external fields on the solidification structures of castings, many studies have investigated electric currents [1,2], magnetic [3] and ultrasonic fields [4,5,6]
Chen et al [13] found that the nucleation rate of metallic melt was increased by super gravity when they studied the change of nucleation energy in an elevated gravity field
Stages, as longof asrelative density difference exists in the solid system study focus (L-L)
Summary
In studying the effect of external fields on the solidification structures of castings, many studies have investigated electric currents [1,2], magnetic [3] and ultrasonic fields [4,5,6]. In centrifugal casting, most existing research has studied mold filling using a centrifugal method [7,8,9,10] and removal of impurities or recovery of valuable components [11,12]. Research on the solidification structure refinement using super gravity is relatively lacking. Some researchers have looked into the effect of super gravity fields or centrifugal fields on refining the solidification of cast structures, the mechanism of grain refinement varies widely among these studies. Zhao et al [14]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
