Shear-Assisted Co-Extrusion of Multi-Alloy Tubes With Bonded Interfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for co-extrusion of dissimilar aluminum alloys, such as hydrostatic extrusion and thermal spray coatings, are either expensive or result in non-uniform material flow and interface issues, while existing solutions like explosive bonding have safety and material constraints, limiting the fabrication of multi-metallic tubes with desirable bonding and ease of manufacturing.
Innovation Solution
Shear-assisted extrusion assemblies and methods that use a billet with distinct inner and outer materials, applying shear force to create extrudates with bonded interfaces, allowing for controlled thickness ratios and flexible fabrication of multi-metallic tubes with varying properties, enabling the co-extrusion of alloys like 6061 and 7075, 1100 and 2024, without the need for elaborate billet fabrication or specific area ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hydrostatic extrusion or indirect extrusion is used for co-extrusion, then multi-metallic tubes can be produced, but the material flow becomes non-uniform and interface bonding is poor
Solution Approach 1:
The extrusion process is segmented into two distinct stages: first conventional extrusion to establish basic geometry, then a separate shear-assisted bonding stage to achieve uniform material flow and interface bonding. This segmentation allows each stage to be optimized independently, resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The invention introduces dynamic shear forces during the extrusion process to actively control material flow. By applying rotational shear to the billet, the system creates controlled differential movement between inner and outer materials, ensuring uniform flow and preventing interface defects while maintaining process simplicity.
2Reliability
If elaborate billet fabrication steps and specific area ratios are employed, then desirable bonding at the interface can be obtained, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The shear-assisted extrusion process enables the billet to self-bond at the interface through controlled shear forces during extrusion. The process automatically achieves uniform material flow and interface bonding without requiring pre-fabricated billets with specific area ratios or elaborate preparation steps, thus maintaining reliability while reducing complexity.
Solution Approach 2:
The invention changes the key parameter from static billet geometry (specific area ratios) to dynamic process parameters (shear force application during extrusion). This allows interface bonding to be achieved through process control rather than precise billet fabrication, reducing device complexity while maintaining bonding reliability.
3Reliability
If thermal spray coatings are used, then surface protection can be achieved, but the coatings are limited to thin layers that crack and spall over time
Solution Approach 1:
Instead of applying separate coating layers that are prone to cracking, the invention creates an integrated multi-metallic composite structure where different aluminum alloys are bonded together through shear-assisted extrusion. This monolithic composite approach eliminates the interface between coating and substrate that causes cracking and spallation in thermal spray applications, while providing the desired surface protection and material properties.
4Ease of manufacture
If explosive bonding is used, then multi-metallic structures can be created, but safety concerns and material constraints limit its application
Solution Approach 1:
The invention replaces the explosive mechanical system with a controlled shear-assisted extrusion process. Instead of using high-explosive forces that create safety hazards and material constraints, the system uses controlled rotational shear forces during extrusion to achieve the same bonding effect, eliminating safety concerns while maintaining ease of manufacture for multi-metallic structures.
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 shear-assisted extrusion process facilitates the production of multi-metallic tubes with sound bonding and variable thicknesses, avoiding thermal stresses and grain growth, and allows for the easy fabrication of difficult-to-extrude material combinations like 1100 and 7075/2024 Al, with improved interface properties and reduced manufacturing complexity.
Implementation Method 1
providing shear-assisted force to a tool operably engaged with the billet to form an extrudate
Data Source
AI summary
Shear-assisted extrusion assemblies are provided. The assemblies can include a billet containing assembly containing a billet comprising a billet outer material and a billet inner material in at least one cross-section; a tool operably engaged with the billet; an extrudate receiving channel configured to receive extrudate from the tool, wherein the extrudate comprises extruded outer material and extruded inner material in at least one cross-section, the extruded outer material being the same material as the billet outer material, and the extruded inner material being the same as the billet inner material. Methods for producing multi-material shear-assisted extrudate are also provided.