Forged aluminum alloy having excellent strength and ductility and method for producing the same

Abstract

Provided is a hot-forged 6xxx-series aluminum alloy having excellent corrosion resistance and still having both high strength and good ductility. A forged 6xxx-series aluminum alloy having a specific chemical composition after solution treatment is further subjected to warm working to introduce dislocations into the forged aluminum alloy microstructure. This allows the forged aluminum alloy after artificial aging to have a microstructure which has a high dislocation density, includes a large proportion of small angle grain boundaries, and has a high average number density of precipitates. Thus, the resulting forged aluminum alloy has a 0.2% yield strength of 400 MPa or more and an elongation of 10% or more and combines properties necessary for suspension parts.

Description

FIELD OF INVENTION[0001]The present invention relates to a forged aluminum alloy having excellent strength and ductility, and a method for producing the same. Hereinafter, “aluminum” is also simply referred to as “AI”.[0002]As used herein, the term “forged material” refers to a forged aluminum alloy produced (plastically worked) by hot forging.[0003]In the present the present invention, the term “forged material” is used not as a term describing a production process of a product, but as a term which is well-known to be generally used as a technical term and / or a patent term for specifying the state of the product.[0004]Aluminum alloy materials, when having different plastic working histories as in hot-forged materials, extruded materials (extrusions), and rolled materials, quite differ from each other in microstructures and properties, even when having identical alloy chemical compositions. Thus, specifying or defining of the alloy chemical compositions, microstructure, and properti...

AI Technical Summary

Benefits of technology

The present invention is about a method to improve the strength and ductility of forged aluminum alloy by controlling the microstructure, including the average dislocation density, the average proportion of small angle grain boundaries, and the average number density of precipitates, through a process of warm working and solution treatment to introduce dislocations and facilitate work hardening. By maintaining an optimal dislocation density, these properties can be achieved and used in high strain regions such as automobile suspension parts, resulting in greater yield strength and good ductility. This method ensures the forged aluminum alloy has superior properties and better performance.

Problems solved by technology

However, even the improvements in chemical compositions and microstructures of hot-forged 6xxx-series aluminum alloys, as disclosed typically in Japanese Patent No. 5110938 and Japanese Patent No. 5723192, are susceptible to improvement so as to give forged aluminum alloys having strength and ductility both at excellent levels, where the strength and ductility properties are mutually contradictory and resist being compatible with each other.