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Article: Determining the Effect of Bi-Sr Interactions on Si Morphology in 319 Al.
- Article from:
- Modern Casting
- Article date:
- June 1, 2000
- Author:
CopyrightCOPYRIGHT 2000 American Foundry Society, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Through experimental data, this article details the Sr/Bi ratio required to effectively modify Si morphology in 319 aluminum and improve melt quality and casting grain structure.
Several elements have been found to refine the size and morphology of eutectic silicon (Si) in hypoeutectic aluminum alloys. This refinement (or modification of the eutectic Si) is defined as a change in the morphology of the eutectic Si from a coarse plate (acicular) to lamellar or fibrous morphologies of varying degrees. For many years, strontium (Sr) has been the most popular choice by North American foundries to modify the eutectic Si phase. The effect of bismuth (Bi) on modification ...