Extruded Brazing Alloy Composition for Corrosion-Resistant Strength

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Solution Overview

Problem

The AA3003 aluminum alloy has poor corrosion resistance, limiting its applications in industries like automotive and air conditioning, where stringent corrosion resistance requirements are needed while maintaining tensile properties and appropriate grain size for extruded and brazed products.

Innovation Solution

An aluminum alloy composition with specific weight percentages of Zn, Mn, Mg, Fe, and optionally Cu and Si is developed to enhance corrosion resistance, tensile properties, and grain size, including up to 0.15% Si, 0.15-0.30% Fe, 0.9-1.2% Mn, 0.03-0.10% Mg, 0.10-0.20% Zn, and up to 0.03% Cu, with (Mg+Mn) exceeding 0.99, to create extruded and brazed products with improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If AA3003 aluminum alloy is used for making extruded and brazed products, then tensile properties and extrudability are maintained, but corrosion resistance is poor

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidtensile properties
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent modifies the chemical composition parameters of the aluminum alloy by adding specific amounts of Zn (0.05-1.0%), Cu (0.05-1.0%), Mg (0.01-0.5%), and Mn (0.01-0.5%), while controlling Si (0-0.5%) and Fe (0-0.5%). This parameter change transforms the alloy from standard AA3003 to an improved composition that achieves both enhanced corrosion resistance and maintained tensile properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite aluminum alloy system by combining multiple alloying elements (Zn, Cu, Mg, Mn, Si, Fe) in specific proportions. This composite approach leverages the synergistic effects of different elements: Zn and Cu for corrosion resistance, Mg and Mn for tensile strength, and controlled Si and Fe for grain size control, resulting in a material that satisfies multiple competing requirements simultaneously

Inventive Principle:
Principle #40Composite materials

2Reliability

If Zn and Cu are added to improve corrosion resistance, then corrosion resistance increases, but tensile properties may deteriorate

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidtensile properties
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the concentration parameters of Zn (0.05-1.0%) and Cu (0.05-1.0%) within specific ranges to achieve corrosion resistance improvement while preventing excessive strength deterioration. Simultaneously, it adjusts Mg (0.01-0.5%) and Mn (0.01-0.5%) content to compensate for any tensile strength loss, maintaining a balanced property profile

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of Zn and Cu additions (which can reduce tensile strength) into a benefit by carefully controlling their concentrations and balancing them with Mg and Mn additions. The controlled presence of these elements provides corrosion resistance while the accompanying Mg and Mn ensure tensile properties are maintained, transforming a potential disadvantage into an advantage

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If Mg and Mn are added to maintain tensile properties, then tensile strength is maintained, but corrosion resistance may decrease

Engineering Contradiction:
Improvetensile propertiesVSAvoidcorrosion resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes the parameter combination of Mg (0.01-0.5%) and Mn (0.01-0.5%) to maintain tensile properties while controlling their upper limits to prevent corrosion resistance deterioration. Simultaneously, it balances these with Zn (0.05-1.0%) and Cu (0.05-1.0%) additions to achieve overall corrosion resistance improvement, creating a balanced compositional profile

Inventive Principle:
Principle #35Parameter changes

4Shape

If Si and Fe are added to control grain size, then formability is improved, but corrosion resistance may be affected

Engineering Contradiction:
Improvegrain sizeVSAvoidcorrosion resistance
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent严格控制Si (0-0.5%) and Fe (0-0.5%) content within low ranges to achieve grain size control and improved formability while minimizing their negative impact on corrosion resistance. This parameter control ensures that the grain-refining benefits are obtained without sacrificing the corrosion resistance provided by the Zn-Cu-Mg-Mn alloying system

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11255002B2Corrosion resistant alloy for extruded and brazed products
Publication Date: 2022.02.22 RIOTINTO ALCAN INT LTD

AI summary

An aluminum alloy for making an extruded and brazed aluminum product, the aluminum alloy comprising, in weight percent, 0.10-0.20 Zn to improve corrosion resistance, 0.9-1.2 Mn, 0.03-0.10 Mg, the sum of Mg and Mn being at least 0.99 to maintain or improve strength, 0.15 to 0.30 Fe to control grain size, up to 0.15 Si, up to 0.03 Cu, up to 0.04 Ti, the balance being aluminum and unavoidable impurities. The alloy may be in the form of extrusion ingots or extruded and brazed aluminum products. A process for making an extruded and brazed aluminum product from the alloy involves homogenizing, extruding, optionally working, and brazing the alloy to form the product.