Grain Refinement in Aluminum Alloys by Acoustic Cavitation Phenomena
Abstract
In this article, ultrasonic method of transmitting forced vibrations to solidifying
aluminum-alloy melts is presented. In the presence of well developed cavitation
situations, a fine and homogeneous microstructure has been observed throughout the
irradiated ingots. The effects produced when high-intensity sonic or ultrasonic waves
are propagated through molten metals can be listed under three main categories:
grain refinement, dispersive effects, and degassing resulting in reduced porosity. It
has been found that vibrations of a mechanical origin are effective in increasing
fluidity by as much as a factor of three and consequently, favorably influence the
mold-filling ability of aluminum alloys. There appear to be two distinct views
regarding the mechanism, which may be explained by the cavitation effects and the
influence of the fluid-flow phenomena.
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- 2007 fascicula9 nr1 [27]