Aluminum Alloy Riveted Assemblies for Low-Corrosion Multi-Material Joining
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Solution Overview
Problem
Conventional methods for joining multi-material assemblies, such as those in the automotive industry, face challenges like galvanic corrosion, recycling issues, and increased costs due to the use of steel rivets, especially when combining aluminum, magnesium, and advanced high-strength steel, as well as difficulties with resistance spot welding due to melting point and solubility differences.
Innovation Solution
The use of aluminum or aluminum alloy rivets with high strain rate riveting techniques, which involve projecting rivets through one component and deforming the material to form an interlock with another, reducing the need for steel rivets and minimizing galvanic corrosion, while maintaining performance and reducing processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel rivets are used to join multi-material assemblies (aluminum, magnesium, advanced high-strength steel), then joining strength and structural integrity are improved, but galvanic corrosion and recycling issues worsen
Solution Approach 1:
The patent applies homogeneity by using aluminum alloy rivets that match the base material (aluminum) of the components being joined. This material matching eliminates galvanic corrosion between dissimilar metals while maintaining the necessary joining strength for multi-material assemblies including aluminum, magnesium, and advanced high-strength steel components.
Solution Approach 2:
The patent changes the material parameter of the rivet from steel to aluminum alloy, fundamentally altering the chemical composition to be compatible with the base materials. This parameter change resolves the galvanic corrosion issue while the rivet design (including drive portion geometry and interlock formation) ensures adequate joining strength is achieved.
2Productivity
If conventional resistance spot welding is used to join multi-material assemblies, then joining efficiency is improved, but feasibility worsens due to melting point differential, galvanic potential and solubility issues
Solution Approach 1:
The patent replaces the thermal process of resistance spot welding with a mechanical riveting process. The aluminum alloy rivet is driven through the components using mechanical force (pressing or impact), forming interlocks without melting or heat-affected zones. This mechanical approach enables joining of dissimilar materials with different melting points, galvanic potentials, and solubility characteristics that would be incompatible with welding.
Solution Approach 2:
The aluminum alloy rivet serves as an intermediary element that mechanically connects dissimilar materials (aluminum, magnesium, advanced high-strength steel) without requiring direct bonding between them. The rivet's drive portion forms interlocks within each component, providing a versatile joining solution that overcomes the limitations of direct welding between incompatible materials.
3Ease of manufacture
If coated boron steel self-piercing rivets are used to join aluminum and steel, then joining capability is improved, but cost and galvanic corrosion issues worsen
Solution Approach 1:
The patent uses aluminum alloy rivets that match the aluminum components being joined, eliminating the need for protective coatings that would be required with steel rivets. This homogeneous material selection maintains joining capability while inherently preventing galvanic corrosion without additional coating layers or protective measures.
4Strength
If steel rivets are used for flow drill screw joining of high strength alloys, then joining strength is improved, but assembly time and cost worsen
Solution Approach 1:
The patent extracts and eliminates the time-consuming steps of flow drilling and thread formation that are required when using steel rivets for high strength alloy joining. The aluminum alloy rivet design allows for direct driving and interlock formation without preliminary hole preparation, significantly reducing assembly time while maintaining joining strength through the interlocking mechanism.
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
This approach enables efficient joining of dissimilar materials like aluminum and magnesium with reduced galvanic corrosion, cost, and recycling challenges, while maintaining performance and enabling lightweighting applications for the automotive industry.
Implementation Method 1
projecting the rivet through at least the first sidewall of the first component to form an affixing interface comprising the second and third sidewalls
Implementation Method 2
deforming the material to form an interlock with another
Data Source
AI summary
Riveted assemblies are provided that can include: a first component having opposing first and second sidewalls; a second component having opposing third and fourth sidewalls, wherein the second sidewall of the first component abuts the third sidewall of the second component to bind and form an affixing interface comprising the second and third sidewall between the first component to the second component; and a rivet extending between a head along a shank to an end, the rivet piercing the first sidewall with the end of the rivet being between the first and fourth sidewalls. Methods for affixing at least two components using a rivet are also provided. The methods can include: providing a first component having opposing first and second sidewalls; providing a second component having opposing third and fourth sidewalls; abutting the second sidewall of the first component to the third sidewall of the second component; providing a rivet extending between a head along a shank to an end; projecting the rivet through at least the first sidewall of the first component to form an affixing interface comprising the second and third sidewalls.