Alloy Surface Cu Enrichment for Bond Durability

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Solution Overview

Problem

Aluminum alloy articles face challenges in achieving strong and durable bonds, especially when bonded with adhesive compositions like epoxy resins, and require improved corrosion resistance for applications in automotive, transportation, electronics, and industrial sectors.

Innovation Solution

The development of aluminum alloy articles with a subsurface portion having a higher concentration of Cu compared to the bulk portion, achieved through a surface-modifying process involving acid etching and alkaline washing, which enhances the atomic concentration ratio of Cu to Mg from 0.2 to 5.0, improving bond durability and corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If aluminum alloy articles are used to replace steel for lightweight applications, then weight is reduced and energy efficiency is improved, but bond durability with adhesive compositions deteriorates

Engineering Contradiction:
ImproveweightVSAvoidbond durability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating a subsurface portion with enhanced Cu concentration specifically at the bonding interface, while the bulk material maintains its original composition. This localized compositional modification improves bond durability without affecting the overall lightweight property of the aluminum alloy article.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the chemical composition parameter by increasing Cu concentration in the subsurface portion and adjusting the Cu-to-Mg atomic ratio to 0.05-5.0. This parameter change enhances the surface's bonding characteristics while maintaining the aluminum alloy's lightweight nature.

Inventive Principle:
Principle #35Parameter changes

2Strength

If traditional welding processes are used on aluminum alloy articles, then bonding strength can be achieved, but the process becomes complex and less suitable for aluminum compared to steel

Engineering Contradiction:
Improvebonding strengthVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent modifies the surface composition parameters (Cu concentration and Cu-to-Mg ratio) to enable effective adhesive bonding, replacing the need for complex welding processes. This allows achieving strong bonds through simpler adhesive application while maintaining suitability for aluminum alloys.

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If aluminum alloy articles are used in harsh environmental conditions, then energy efficiency and lightweight properties are improved, but corrosion resistance may deteriorate

Engineering Contradiction:
ImproveweightVSAvoidcorrosion resistance
Core Design Contradiction:
Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by modifying the subsurface portion's composition specifically to enhance corrosion resistance, while the bulk material maintains its lightweight properties. The enhanced Cu concentration at the surface provides improved protection against environmental degradation.

Inventive Principle:
Principle #3Local quality

4Reliability

If the subsurface portion has higher Cu concentration to improve bond durability, then bonding performance is enhanced, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvebond durabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-modifying the subsurface composition during the manufacturing process (through controlled rolling or surface treatment) before the bonding operation. This preliminary Cu enrichment ensures optimal bonding performance is achieved without requiring complex post-processing or specialized bonding equipment.

Inventive Principle:
Principle #10Preliminary action

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 modified surface composition significantly enhances bond durability and corrosion resistance, making the aluminum alloy articles more suitable for bonding with other materials and increasing their lifespan in harsh environmental conditions.

Implementation Method 1

a surface-modifying process involving acid etching and alkaline washing

Methodology Applied
Scientific EffectSelective etching:

Implementation Method 2

a surface-modifying process involving acid etching and alkaline washing

Methodology Applied
Scientific EffectAlkaline washing:

Data Source

PatentEP3669015B1Aluminum alloy articles having improved bond durability and inert surface aluminum alloy articles and methods of making and using the same
Publication Date: 2023.08.02 NOVELIS INC(US)
  • EP3669015B1 patent drawingFigure 1
  • EP3669015B1 patent drawingFigure 2
  • EP3669015B1 patent drawingFigure 3

AI summary

The present disclosure generally provides aluminum alloy articles having improved bond durability at certain surfaces of the article. The disclosure also provides methods of making such materials, for example, via a selective etching process, as well as methods of using such articles in applications that involve bonding the article to other articles, such as other aluminum articles. The disclosure also provides articles of manufacture made from such articles, including bonded aluminum articles. The disclosure also provides aluminum alloy articles having an inert or neutralized surface. The inert or neutralized surfaces described herein are characterized by surfaces containing oxidized copper. Also described herein are methods including etching a surface of the aluminum alloy articles with an oxidant. The resulting aluminum alloy articles exhibit desirable bond durability properties and exceptional corrosion resistance. The disclosure also provides various end uses of such articles, such as in automotive, transportation, electronics, and industrial applications.