Copper-Molybdenum Composite Plate Bonding to Prevent Brazing Cracks
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Solution Overview
Problem
The existing heat radiation plates experience cracks between copper and copper-molybdenum layers due to heat during brazing, leading to an increased linear expansion coefficient.
Innovation Solution
A composite material with alternating copper layers and molybdenum powder compact impregnated with copper layers, bonded using a hot roll bonding method, maintains a low linear expansion coefficient and high thermal conductivity even after heat application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper layers and copper-molybdenum layers are alternately layered and bonded by brazing, then thermal conductivity is improved, but cracks occur between layers due to heat causing increased linear expansion coefficient
Solution Approach 1:
The invention changes the bonding method from brazing to hot roll bonding, altering the thermal and mechanical parameters of the bonding process. This avoids the high-temperature exposure that causes crack formation while maintaining effective thermal conduction through the layered structure.
Solution Approach 2:
The invention uses a composite structure of copper and copper-molybdenum layers where each material contributes its advantageous properties. Copper provides high thermal conductivity while molybdenum reinforces the structure, creating a composite that maintains both thermal performance and structural integrity under thermal stress.
2Strength
If high heat is applied during brazing, then bonding between layers is improved, but crack generation increases due to thermal expansion
Solution Approach 1:
The invention replaces the thermal-bonding mechanism of brazing with a mechanical-bonding mechanism through hot roll bonding. This substitution reduces reliance on high-temperature thermal fields, thereby minimizing thermally-induced crack generation while achieving sufficient bonding strength through mechanical deformation and interdiffusion.
Solution Approach 2:
The bonding temperature and time parameters are optimized for hot roll bonding rather than brazing. The process uses controlled heating followed by mechanical rolling, changing the thermal-mechanical parameter profile to avoid the harmful effects of prolonged high-temperature exposure that cause crack formation.
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 composite material maintains a low linear expansion coefficient and high thermal conductivity, reducing the likelihood of cracks and enhancing thermal conductivity in the thickness direction.
Implementation Method 1
a layer of a molybdenum powder compact impregnated with copper; high thermal conductivity, reducing the likelihood of cracks and enhancing thermal conductivity in the thickness direction
Implementation Method 2
bonded using a hot roll bonding method
Data Source
AI summary
A composite material has a plate shape and has a first surface and a second surface. The second surface is opposite to the first surface. The composite material includes a plurality of first layers and at least one second layer. The first layers and the second layer are alternately layered along a thickness direction of the composite material such that the first layers are located at the first surface and the second surface. Each of the first layers is a layer including copper. The second layer is a layer of a molybdenum powder compact impregnated with copper. A compressive residual stress of 50 MPa or less acts on each of the first layer located at the first surface and the first layer located at the second surface.