Al-Cu Clad 2xxx Aerospace Product for Damage-Resistant Forming

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Solution Overview

Problem

Current aerospace products using 1XXX-series aluminium alloys for cladding are soft and prone to surface damage during handling and forming operations, leading to issues like die-sticking and reduced corrosion resistance.

Innovation Solution

A rolled composite aerospace product featuring a 2XXX-series core layer coupled with an Al-Cu alloy cladding layer, which provides improved corrosion resistance and formability due to its higher hardness and formability characteristics, achieved through roll bonding and specific heat treatment processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If 1XXX-series aluminium alloy is used for cladding layer, then corrosion resistance is improved, but surface damage susceptibility increases during handling and forming operations

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidsurface damage susceptibility
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies composite material structure by combining 2XXX-series core alloy with Al-Cu clad layer. The clad layer contains 0.2-2.8% Cu (preferably 0.5-1.5%) which provides both corrosion protection and improved surface hardness compared to traditional 1XXX-series cladding, reducing surface damage susceptibility while maintaining corrosion resistance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If 1XXX-series aluminium alloy is used for cladding layer, then corrosion protection is enhanced, but die-sticking occurs during forming operations

Engineering Contradiction:
Improvecorrosion protectionVSAvoidforming operation difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the clad layer by incorporating 0.2-2.8% Cu (preferably 0.5-1.5%) instead of using pure 1XXX-series aluminium. This parameter change increases the hardness and reduces the adhesiveness of the clad layer surface, preventing die-sticking during forming operations while maintaining adequate corrosion protection.

Inventive Principle:
Principle #35Parameter changes

3Strength

If Al-Cu alloy with higher Cu content is used for cladding layer, then hardness and formability are improved, but corrosion resistance may be compromised

Engineering Contradiction:
Improvehardness and formabilityVSAvoidcorrosion resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes the Cu content parameter within a specific range of 0.2-2.8% (preferably 0.5-1.5%). This parameter optimization achieves the right balance: sufficient Cu content to provide improved hardness and formability, while limiting it to maintain adequate corrosion resistance. The controlled composition prevents excessive Cu from compromising the protective function of the clad layer.

Inventive Principle:
Principle #35Parameter changes

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 Al-Cu alloy cladding enhances the overall strength and corrosion resistance of the composite product, reducing surface damage and enabling weight savings or increased strength while maintaining corrosion protection, and allows for easier recycling.

Implementation Method 1

The cladding layer is usually of higher purity which corrosion protects the AA2024 core alloy

Methodology Applied
Scientific EffectGalvanic corrosion resistance: Crevice Corrosion

Implementation Method 2

The rolled composite aerospace product featuring a 2XXX-series core layer coupled with an Al-Cu alloy cladding layer, which provides improved corrosion resistance and formability due to its higher hardness and formability characteristics, achieved through roll bonding and specific heat treatment processes

Methodology Applied
Scientific EffectRoll bonding: Welding

Data Source

PatentEP3904073B1Clad 2xxx-series aerospace product
Publication Date: 2023.05.31 NOVELIS KOBLENZ GMBH
  • EP3904073B1 patent drawingFigure 1~2
  • EP3904073B1 patent drawingFigure 3

AI summary

The invention relates to a rolled composite aerospace product comprising a 2XXX-series core layer and an Al-Cu alloy clad layer coupled to at least one surface of the 2XXX-series core layer, wherein the Al-Cu alloy is an aluminium alloy comprising about 0.06% to 2.8% Cu, and preferably about 0.10% to 1.8% Cu. The rolled composite aerospace product is ideally suitable for structural aerospace parts. The invention further relates to a method of manufacturing a rolled composite aerospace product.