Thermal Pyrolytic Graphite Aluminum Composite Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current thermally conductive composite materials face challenges in achieving a balance between thermal conductivity and physical strength, particularly when combining materials like thermal pyrolytic graphite and aluminum alloys, as they often require mechanical methods that lack metallurgical bonding and result in structural integrity issues.
Innovation Solution
A thermally conductive composite material is created by embedding thermal pyrolytic graphite plugs into an aluminum or aluminum alloy member using a eutectic alloy interface formed by the combination of aluminum, thermal pyrolytic graphite, and silicon, achieved through liquid interface diffusion bonding under pressure and temperature, which provides a strong and directional thermal conduction path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal pyrolytic graphite plugs are embedded in aluminum alloy members using mechanical methods, then thermal conductivity is improved, but structural integrity and bonding strength deteriorate
Solution Approach 1:
Silicon serves as an intermediary material that forms a eutectic alloy at the interface between thermal pyrolytic graphite plugs and aluminum alloy members. This eutectic interface layer creates metallurgical bonding, resolving the contradiction by providing both strong structural adhesion and maintained thermal conductivity pathways through the graphite plugs.
Solution Approach 2:
The invention changes the bonding mechanism from mechanical attachment to metallurgical bonding through eutectic alloy formation. By controlling the chemical composition (adding silicon) and thermal parameters (heating to eutectic temperature), the bonding strength parameter is dramatically improved while maintaining the thermal conductivity function.
2Temperature
If thermal pyrolytic graphite is used to enhance thermal conductivity, then thermal performance is improved, but physical strength is reduced
Solution Approach 1:
The invention creates a composite material system consisting of thermal pyrolytic graphite plugs embedded in aluminum alloy members with a silicon-based eutectic interface. This composite structure combines the high thermal conductivity of graphite with the mechanical strength of aluminum alloy, resolved through metallurgical bonding that prevents delamination and structural failure.
Solution Approach 2:
The silicon-based eutectic interface acts as a mediator that bonds the graphite plugs to the aluminum alloy matrix. This intermediary layer ensures that the graphite plugs remain firmly anchored, transferring mechanical loads effectively while maintaining thermal conductivity pathways.
3Ease of manufacture
If mechanical bonding methods are used to attach thermal pyrolytic graphite, then ease of manufacture is improved, but bonding strength and reliability deteriorate
Solution Approach 1:
The invention changes the bonding process from mechanical attachment to thermal processing that forms a eutectic alloy. By controlling temperature and composition parameters, reliable metallurgical bonding is achieved. The process remains manufacturable through standardized heat treatment procedures and controlled silicon addition.
Solution Approach 2:
The bonding process utilizes the phase transition of the silicon-aluminum system to form a eutectic alloy at a specific temperature. This phase transition creates a low-melting-point interface layer that flows and bonds the graphite plugs to the aluminum alloy, providing reliable adhesion through a controlled thermal process.
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 solution enhances both thermal conductivity and physical strength, offering a material suitable for aerospace and commercial applications with improved durability and reduced thermal expansion stresses, while maintaining minimal impact on thermal transfer.
Implementation Method 1
The plugs are secured to the aluminum or aluminum alloy member by an eutectic alloy interface. The eutectic alloy interface is formed by the aluminum or aluminum alloy, the thermal pyrolytic graphite and silicon.
Implementation Method 2
An amount of silicon is applied to the plugs and the depressions or apertures. The amount of silicon is sufficient for liquid interface diffusion bonding. Bonding energy is applied to the blank of aluminum or aluminum alloy with the inserted plugs. The binding energy is applied so that the thermal pyrolytic graphite, the aluminum or aluminum alloy and the silicon form a eutectic alloy.
Data Source
AI summary
A thermally conductive composite material, a thermal transfer device made of the material, and a method for making the material are disclosed. Apertures or depressions are formed in aluminum or aluminum alloy. Plugs are formed of thermal pyrolytic graphite. An amount of silicon sufficient for liquid interface diffusion bonding is applied, for example by vapor deposition or use of aluminum silicon alloy foil. The plugs are inserted in the apertures or depressions. Bonding energy is applied, for example by applying pressure and heat using a hot isostatic press. The thermal pyrolytic graphite, aluminum or aluminum alloy and silicon form a eutectic alloy. As a result, the plugs are bonded into the apertures or depressions. The composite material can be machined to produce finished devices such as the thermal transfer device. Thermally conductive planes of the thermal pyrolytic graphite plugs may be aligned in parallel to present a thermal conduction path.