Clad Sheet Product with Segmented Alloy Composition
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Solution Overview
Problem
Current aluminum alloy sheets, particularly those in the 6XXX series, face a compromise between strength and formability, and lack adequate corrosion resistance, making them less suitable for high-strength applications while being challenging to recycle effectively.
Innovation Solution
A composite aluminum sheet product is developed with a 6XXX series core and 6XXX series clad layers, optimized in Mg, Si, Cu, Fe, and Mn content, allowing for enhanced strength, formability, and corrosion resistance, achieved through a co-casting method and specific heat treatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high strength aluminium alloy (AA6111) is used, then mechanical strength is improved, but formability deteriorates
Solution Approach 1:
The aluminium alloy sheet is segmented into a composite structure with a core layer (AA6111) and clad layers (AA6003/AA6005), where each layer has different properties. The core provides strength while the clad layers provide formability, resolving the contradiction between strength and formability in monolithic alloys.
Solution Approach 2:
Different regions of the sheet have different alloy compositions optimized for different functions. The core layer has high Cu content (0.7-1.5%) for strength, while the clad layers have lower Cu (0.05-0.5%) and higher Mg (0.8-1.8%) for formability and corrosion resistance, allowing each region to perform its specific function optimally.
2Strength
If 6XXX series alloy with high Si content is used, then strength is improved, but corrosion resistance deteriorates
Solution Approach 1:
The clad layers have optimized Si content (0.1-0.6%) that balances strength and corrosion resistance, while the core layer can have higher Si content (0.2-1.8%) for strength. This local differentiation allows the material to achieve both high strength and good corrosion resistance.
Solution Approach 2:
The composite structure combines 6XXX series alloys with different compositions in the core and clad layers. This composite approach allows the material to exhibit properties that are superior to either layer alone, achieving both high strength and corrosion resistance.
3Ease of manufacture
If 5XXX series alloy clad layer is used, then formability is improved, but recyclability deteriorates
Solution Approach 1:
Instead of changing the alloy series (which would affect recyclability), the invention changes the parameters within the 6XXX series by adjusting Mg, Si, and Cu content. The clad layers use 6XXX series alloys with optimized parameters to achieve formability without compromising recyclability, as both core and clad are from the same alloy series.
4Device complexity
If conventional monolithic alloy is used, then manufacturing simplicity is maintained, but mechanical performance deteriorates
Solution Approach 1:
The sheet is segmented into core and clad layers with different compositions, achieving superior mechanical performance. The co-casting process integrates this segmentation into a single manufacturing step, maintaining manufacturing simplicity while dramatically improving mechanical properties compared to monolithic alloys.
Solution Approach 2:
The composite structure of core and clad layers with different alloy compositions provides enhanced mechanical performance, including higher strength, improved formability, and better corrosion resistance, while the co-casting process keeps manufacturing relatively simple.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The product exhibits superior mechanical performance, improved bake hardenability, better formability, and enhanced corrosion resistance compared to conventional monolithic high-strength aluminum sheets, while being easier to recycle and more valuable as scrap material.
Implementation Method 1
specific heat treatment processes
Data Source
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AI summary
The invention relates to a clad sheet product comprising a core layer and at least one clad layer wherein the core comprises an alloy of the following composition in weight %: Mg 0.90 - 1.40; Si 0.90 - 1.40; Cu 0.75 - 1.40; Mn <0.40; Cr <0.20; Fe <0.30; others <0.05 each and <0.15 in total; balance aluminium; and the at least one clad layer comprises an alloy of the following composition in weight %: Mg 0.30 - 0.70; Si 0.30 - 0.80; Cu <0.30; Mn <0.30; Fe <0.30; others <0.05 each and <0.15 in total; balance aluminium. Furthermore, the invention relates to a method of producing a clad sheet product comprising a core layer and at least one clad layer wherein the core comprises an alloy of the following composition in weight %: Mg 0.90 - 1.40; Si 0.90 - 1.40; Cu 0.75 - 1.40; Mn <0.40; Cr <0.20; Fe <0.30; others <0.05 each and <0.15 in total; balance aluminium, and the at least one clad layer comprises an alloy of the following composition in weight %: Mg 0.30 - 0.70; Si 0.30 - 0.80; Cu <0.30; Mn <0.30; Fe <0.30; others <0.05 each and <0.15 in total; balance aluminium, comprising the steps of : preparing a composite ingot having one core layer and at least one clad layer; performing a homogenization treatment; hot rolling the homogenized composite ingot to a hot rolled sheet product; cold rolling the hot rolled sheet product to a cold rolled sheet product; performing a solutionizing treatment; and quenching the solutionized cold rolled sheet product, followed by pre-aging and slow cooling to room temperature.