Functionally Graded Cladding via Shear-Assisted Extrusion
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Solution Overview
Problem
Existing methods for cladding materials, such as extrusion and rolling, struggle with non-uniform thickness, porous interfaces, and lack of metallurgical bonding, especially when working with anisotropic materials like magnesium, titanium, or zirconium, and are unable to control the graded interface or create desired textures in the final component.
Innovation Solution
A shear assisted extrusion process using a rotating scroll face to feed cladding and base materials through a shear assisted extrusion device, allowing for controlled texture and grain size variation across the wall thickness, enabling improved metallurgical bonding and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional extrusion or rolling techniques are used to clad materials, then cladding can be applied to improve corrosion resistance and mechanical properties, but the process produces non-uniform thickness, porous interfaces, and lacks metallurgical bonding
Solution Approach 1:
The patent applies friction stir processing by changing the fundamental processing parameters from conventional extrusion/rolling. A rotating tool with specific geometry (shoulder and probe) is used to locally modify material properties through controlled friction and stirring, achieving uniform cladding thickness and metallurgical bonding that conventional techniques cannot produce
Solution Approach 2:
The patent replaces the conventional mechanical extrusion/rolling system with a friction-based stirring system. The rotating tool generates localized plasticization through friction heat and mechanical stirring, fundamentally changing the material processing mechanism to achieve superior interface quality and bonding
2Reliability
If conventional extrusion or rolling techniques are used to clad anisotropic materials like magnesium, titanium, or zirconium, then cladding can be applied, but the process creates porous interfaces and lacks metallurgical bonding
Solution Approach 1:
The patent uses friction stir processing to change the processing parameters fundamentally. The rotating tool creates localized plasticization through friction heat and mechanical stirring, enabling metallurgical bonding at the interface without the porous defects characteristic of conventional techniques, even for anisotropic materials
Solution Approach 2:
The rotating tool acts as an intermediary that facilitates metallurgical bonding. Through controlled friction and stirring, it creates a plasticized zone that enables intimate contact and bonding between dissimilar materials, overcoming the interface quality problems of conventional direct bonding methods
3Manufacturing precision
If conventional extrusion techniques are used, then materials can be processed, but the process is slow and unable to control the graded interface or create desired texture in the final component
Solution Approach 1:
The patent applies preliminary action by using the rotating tool to create desired texture and microstructure during the cladding process itself. The controlled stirring and friction heat generate the required grain structure and material flow patterns before final cooling, eliminating the need for separate texture control steps
Solution Approach 2:
The patent changes processing parameters by using friction-based plasticization instead of conventional extrusion. This enables control over graded interfaces and texture through tool rotation speed, plunge depth, and feed rate, while maintaining high productivity through continuous processing
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 process achieves uniform cladding with tailored properties, enhancing mechanical properties, reducing brittleness and corrosion susceptibility, and enabling the extrusion of brittle intermetallic materials not possible with conventional methods.
Implementation Method 1
significant heating occurs due to friction, thus softening the underlying billet material
Implementation Method 2
force the underlying material to flow plastically
Data Source
AI summary
A shear assisted extrusion process for producing cladded materials wherein a cladding material and a material to be cladded are placed in sequence with the cladded material positioned to contact a rotating scroll face first and the material to be cladded second. The two materials are fed through a shear assisted extrusion device at a preselected feed rate and impacted by a rotating scroll face to generate a cladded extrusion product. This process allows for increased through wall strength and decreases the brittleness in formed structures as compared to the prior art.