System and method to stabilize transition metal precipitates in cast aluminum alloys during primary solidification

Abstract

A system for casting an aluminum alloy includes a first chamber for containing a first melt at a first temperature, a second chamber for containing second melt at a second temperature that is lower than the first temperature, a mixing chamber in communication with the first chamber and the second chamber for simultaneously receiving and mixing the first melt from the first chamber with the second melt from the second chamber, and a mold chamber in communication with the mixing chamber and for receiving the mixed melt.

Description

FIELD[0001]The present disclosure relates to a system and method to stabilize transition metal precipitates in cast aluminum alloys during primary solidification.INTRODUCTION[0002]This introduction generally presents the context of the disclosure. Work of the presently named inventors, to the extent it is described in this introduction, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against this disclosure.[0003]Aluminum cast alloys have widespread applications for structural components in the automotive, aerospace, and general engineering industries because of good castability, corrosion resistance, machinability, and high strength-to-weight ratio. Regarding castability, alloy compositions having lower Silicon content have been thought to inherently produce poor castings due to a wider freezing range and the reduced latent heat. Lower Silicon alloys are difficult to c...

AI Technical Summary

Benefits of technology

The patent text describes a way to improve the properties of cast aluminum alloys by using a certain process. This process helps increase the temperature and wear durability of the alloy, while also improving its ability to refine grain without the need for additional materials. This results in better quality castings with fewer defects.

Problems solved by technology

Regarding castability, alloy compositions having lower Silicon content have been thought to inherently produce poor castings due to a wider freezing range and the reduced latent heat.

Lower Silicon alloys are difficult to cast, they possess less fluidity for mold filling and lower latent heat for feeding solidification shrinkage.

Further, lower Silicon alloys are prone to a hot tearing defect during solidification in which a partially solidified casting pulls itself apart doe to the contraction of the casting as it cools, which leaves fissures that may result in leaking, reduced mechanical properties and lower fatigue life.

The addition of transition metals to the metal composition exacerbates both castability and fatigue properties due to these manufacturing problems.

Alternatively, alloy compositions having higher Silicon content are increasingly difficult to machine and have lower ductility and fracture toughness due to coarser primary silicon particles.

In attempting to expand or improve the use of aluminum alloys in additional applications that can reap the benefits that aluminum alloys offer, existing aluminum alloy casting composition and processes have fallen short of success in high temperature applications.

However, the presence of Silicon within the Aluminum alloy melt poisons or reduces the ability for the alloy to form high temperature phases.

This reduces that capability for these alloys to be used in some high temperature applications.

The reduction in high temperature phases reduces the durability of the casting in high temperature applications.

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