Rotational Hammer Riveted Assembly for Mixed-Material Bonding
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Solution Overview
Problem
Conventional welding and riveting techniques fail to form a metallurgical bond between dissimilar materials like magnesium and aluminum alloys with other metals, ceramics, or carbon fiber composites, leading to brittle interfaces and compliance issues under mechanical loading, and are limited by the low formability and ductility of high-strength aluminum and magnesium alloys.
Innovation Solution
The rotational hammer riveting (RHR) technique generates heat and pressure to create a metallurgical bond between a rivet stop head and metal-comprising substrates, such as magnesium or aluminum sheets, using a rotating tool to deform the rivet shaft and substrate, forming a mixed interface that seals against corrosive electrolyte penetration and improves the formability of tempered alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional welding techniques are used to join dissimilar materials, then joining strength is achieved, but brittle intermetallic compounds form at the interface leading to interfacial fracture
Solution Approach 1:
The patent introduces a transition layer or intermediate material between dissimilar metals to prevent direct contact and intermetallic compound formation. This intermediary layer acts as a buffer that maintains bonding strength while preventing the harmful chemical reactions that cause brittleness at the interface.
Solution Approach 2:
The patent modifies process parameters such as temperature, pressure, and heating rate during joining to control the formation of intermetallic compounds. By precisely controlling these parameters, the process achieves adequate bonding strength while limiting the growth of brittle intermetallic phases at the interface.
2Ease of manufacture
If conventional riveting is used to join materials, then mechanical fastening is achieved, but no metallurgical bond forms leading to compliance under shock and vibration
Solution Approach 1:
The patent combines mechanical fastening with metallurgical bonding in a single riveting process. The rivet creates both mechanical interlocking through deformation and metallurgical bonding through controlled plastic deformation and mixing of materials, eliminating the compliance issues of conventional mechanical fastening alone.
Solution Approach 2:
The patent replaces pure mechanical fastening with a process that uses mechanical force to create metallurgical bonding. The riveting process generates sufficient plastic deformation and heat to create a metallurgical bond, substituting the need for separate mechanical and chemical bonding systems.
3Strength
If high-strength tempered aluminum alloys are used, then strength to weight ratio is improved, but formability decreases making riveting impossible at room temperature
Solution Approach 1:
The patent changes the temperature parameter during riveting to enable formability of tempered alloys. By performing riveting at elevated temperatures, the material becomes more ductile and formable, allowing the riveting process to proceed without requiring annealing or special storage conditions.
Solution Approach 2:
The patent employs a rapid, impulsive riveting action that creates localized plastic deformation before the material can harden. This periodic, high-speed deformation allows forming of tempered alloys without requiring them to be in a soft, annealed state.
4Strength
If fusion welding is used to join metals to CFRP, then joining is achieved, but melting at the metal-CFRP interface leads to interfacial fracture
Solution Approach 1:
The patent replaces thermal fusion welding with a mechanical joining process that uses plastic deformation and friction heat instead of bulk melting. This substitution avoids the harmful melting at the metal-CFRP interface while still achieving strong bonding through mechanical interlocking and localized metallurgical bonding.
Solution Approach 2:
The patent creates localized bonding zones with controlled heating and deformation rather than widespread melting. The joining process concentrates energy and mechanical action at specific points to create strong bonds without subjecting the entire interface to conditions that would cause melting and degradation of the CFRP.
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
RHR enables strong, flexible multi-material assemblies with increased riveting speed, overcoming the limitations of conventional methods by forming a metallurgical bond that enhances mechanical properties and seals against corrosion, particularly effective for joining high-strength aluminum and magnesium alloys with carbon fiber reinforced polymers and steel.
Implementation Method 1
The rotational hammer riveting (RHR) technique generates heat and pressure to create a metallurgical bond between a rivet stop head and metal-comprising substrates
Implementation Method 2
using a rotating tool to deform the rivet shaft and substrate, forming a mixed interface
Implementation Method 3
forming a metallurgical bond that enhances mechanical properties and seals against corrosion
Data Source
AI summary
Riveted assemblies are provided that can include a substrate extending between two ends to define opposing substrate surfaces having a first opening extending between the opposing substrate surfaces; a metal-comprising substrate extending between two ends to define opposing metal-comprising substrate surfaces having a second opening extending between the opposing metal-comprising substrate surfaces. The riveted assemblies can further provide that the first and second openings complement one another when the substrate and metal-comprising substrate are engaged; and a rivet shaft extends through the openings and engages the substrate with the rivet head and the metal-comprising substrate with the rivet stop head, at least a portion of the stop head being mixed with, and forming a metallurgical bond with the metal-comprising substrate. Assemblies are provided that can include a rivet stop head mixed with, and metallurgically bonded with a metal-comprising substrate.Methods for affixing substrates to one another are also provided. The methods can include providing a substrate defining an opening configured to receive a rivet shaft; providing a metal-comprising substrate defining a complimentary opening; operatively engaging the substrates with the rivet shaft; and forming a stop head from the rivet shaft to affix the substrates. The method further includes that the stop head mixes with, and forms a metallurgical bond with the metal-comprising substrate. Methods for mixing materials to form a metallurgical bond are also provided. The methods can include forming a metallurgical bond between a stop head of a rivet and a metal-comprising substrate.