Ti Brazing Foils via Cold-Rolled Multi-Layer Composite
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Solution Overview
Problem
Conventional methods for producing titanium-based brazing alloys in thin foil form are challenging due to their brittleness, which complicates cold working and results in non-uniform deformation and embrittlement, limiting the thickness and mechanical properties of brazed components.
Innovation Solution
A roll bonding process is used to create multi-layered composite strips and foils with titanium and zirconium sandwiched between copper and nickel layers, forming a metallic bond without intermediate heat treating, allowing for significant thickness reduction and improved chemical composition control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional cold working process is used to produce thin gauge Ti-based brazing alloys, then thickness reduction is achieved, but the material becomes brittle and exhibits non-uniform deformation
Solution Approach 1:
The Ti-based brazing alloy is divided into multiple discrete layers (Ti layer, Zr layer, Cu layer, Ni layer) that are bonded together. This segmentation allows each layer to deform more uniformly during cold working while maintaining overall structural integrity, preventing the brittleness and non-uniform deformation that would occur in a monolithic Ti alloy of the same thin gauge.
Solution Approach 2:
The invention creates a composite material structure consisting of multiple metallic layers (Ti, Zr, Cu, Ni) bonded together. This composite structure combines the advantages of each material: Ti and Zr provide low melting point and brazing properties, while Cu and Ni layers provide ductility and formability. The composite structure enables thin gauge production through cold working without the brittleness issues of conventional Ti alloys.
2Ease of operation
If intermediate heat treating is applied during cold working, then ductility is improved, but processing time and complexity increase
Solution Approach 1:
The invention changes the structural parameter of the material from a monolithic Ti alloy to a multi-layer composite structure. This parameter change fundamentally alters the deformation behavior, allowing the material to achieve high ductility through cold working alone without requiring intermediate heat treating steps. The Cu and Ni layers act as ductile matrices that accommodate deformation, eliminating the need for thermal processing.
Solution Approach 2:
The invention extracts the heat treating step from the conventional cold working process by designing a multi-layer composite structure that inherently provides the necessary ductility through its composition. The Cu and Ni layers are specifically selected to provide room-temperature ductility, making intermediate heat treating unnecessary and thus eliminating the associated time loss and process complexity.
3Manufacturing precision
If Ti layer is placed in the middle of the multi-layer structure, then uniform chemistry and thin finish thickness are achieved, but the Ti layer is more susceptible to embrittlement
Solution Approach 1:
The invention uses a composite material structure where the Ti layer is sandwiched between Zr layers, which are in turn surrounded by Cu and Ni layers. This composite structure protects the central Ti layer from direct exposure to the environment and from excessive deformation during cold working. The outer Cu and Ni layers act as protective and ductile matrices that absorb deformation energy, preventing embrittlement of the Ti layer while maintaining uniform finish thickness.
Solution Approach 2:
The multi-layer structure provides beforehand cushioning for the Ti layer by placing ductile Cu and Ni layers on the outer surfaces. These outer layers serve as a cushion that absorbs deformation stress and protects the Ti layer from embrittlement during cold working. The Zr layers provide an intermediate protective barrier, creating a layered defense system that preserves Ti layer integrity while enabling uniform thin gauge production.
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 the production of titanium-based brazing alloys with lower melting points, reducing embrittlement and improving mechanical properties, while avoiding the need for heat treating, thus enhancing ductility and fatigue resistance, and allowing for continuous coil formation in thin gauge.
Implementation Method 1
A roll bonding process is used to create multi-layered composite strips and foils with titanium and zirconium sandwiched between copper and nickel layers, forming a metallic bond without intermediate heat treating
Implementation Method 2
The layers are cold rolled to a desired thickness and the layers are metallurgically bonded together
Data Source
AI summary
A method for producing titanium alloy brazing strips and the resulting brazing strips and/or foils. The method uses a cold-rolling process without heat treating to generate a titanium based multi-layer alloy strip or foil made up of discrete layers of titanium and an additional layer or layers of one or more metals, such as zirconium, nickel and/or copper, for example, or alloys thereof, with the layer of titanium roll bonded without heat treating to the layers of the additional metal(s). The resulting strip or foil can include, for example, Cu/Ti/Cu, Ni/Ti/Ni, Ni/Ti/Cu, Cu/Ni/Ti/Ni/Cu, Ni/Cu/Ti/Cu/Ni, Ni/Cu/Ni/Ti/Ni/Cu/Ni, Ni/Zr/Cu/Ti/Cu/Zr/Ni and Ni/Ti/Cu/Zr/Cu/Ti/Ni among other combinations. The resulting strip or foil can be used for brazing, creating an alloy of the weight percentage of the original materials.