Tungsten-Copper Composite Joining for High-Temperature Strength
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Solution Overview
Problem
Tungsten-copper-based composite materials exhibit low heat resistance due to limitations in joining methods, particularly with conventional brazing techniques that use nickel-based materials, which are hazardous and restrict shape flexibility or require pure copper, limiting their applications.
Innovation Solution
Incorporating an insert metal such as titanium, zirconium, or hafnium into the copper-based member at specific concentrations (0-5.0 atomic %) near the joining interface, utilizing metallurgical reactions to enhance the melting point and heat resistance of the joining portion, while avoiding the formation of brittle intermetallic compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional brazing methods using nickel-based materials are used to join tungsten and copper, then the joining strength is improved, but the heat resistance deteriorates due to low melting point of the brazing material
Solution Approach 1:
A copper-based intermediate layer containing 0-5 atomic % of titanium, zirconium, or hafnium is introduced between the tungsten and nickel-based brazing material. This intermediate layer acts as a mediator that improves wetting and bonding at the tungsten-brazing interface while maintaining high heat resistance, as the copper-based material has a higher melting point than the nickel-based brazing material.
Solution Approach 2:
The composition of the intermediate layer is precisely controlled with 0-5 atomic % of reactive metals (titanium, zirconium, or hafnium). This parameter optimization ensures sufficient metallurgical reaction to improve bonding without forming excessive brittle intermetallic compounds that would compromise heat resistance.
2Strength
If nickel-based brazing materials are used for joining, then the joining strength is improved, but safety deteriorates due to hazardous properties of nickel
Solution Approach 1:
The copper-based intermediate layer serves as a protective intermediary between the hazardous nickel-based brazing material and the environment, reducing direct exposure to nickel while maintaining the joining strength benefits of nickel-based materials.
3Ease of manufacture
If pure copper is used as the copper-based member, then the ease of manufacture is improved, but adaptability deteriorates due to shape restrictions
Solution Approach 1:
The copper-based intermediate layer is combined with small amounts (0-5 atomic %) of reactive metals (titanium, zirconium, or hafnium) to create a composite material that maintains the formability of copper while adding controlled metallurgical reactivity to improve bonding with tungsten, thereby enabling greater shape flexibility without sacrificing ease of manufacture.
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 approach results in a composite material with improved heat resistance and mechanical strength, maintaining structural integrity at high temperatures without the use of hazardous materials and allowing for varied shapes and compositions, thus overcoming the limitations of conventional joining methods.
Implementation Method 1
utilizing metallurgical reactions to enhance the melting point and heat resistance of the joining portion
Implementation Method 2
maintaining structural integrity at high temperatures
Data Source
AI summary
A composite material includes: a first member containing tungsten as a primary component; a second member containing copper as a primary component, the second member being joined to the first member; and a metal containing at least one metal selected from a group consisting of titanium, zirconium, and hafnium, the metal being present in the second member, wherein a concentration of the metal is more than 0 atomic % and less than or equal to 5.0 atomic % at a location of 5 μm from a joining interface between the first member and the second member toward the second member side.