Porous Aluminum Sintered Compact Bonding via Eutectic Reaction
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Solution Overview
Problem
Existing methods for producing porous aluminum sintered compacts face challenges such as low porosity, inhibited substrate bonding due to oxide films, insufficient strength, and inefficient production processes, leading to compacts that are prone to breakage and require cautious handling.
Innovation Solution
The use of a Ti—Al compound and eutectic element compound, capable of eutectic reaction with Al, to form junctions between aluminum substrates, which suppresses diffusion and enhances bonding, allowing for high porosity and strength while reducing shrinkage and binder content, and the formation of pillar-shaped protrusions for improved structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum substrates are sintered each other directly, then bonding between substrates should be achieved, but strong oxide films on the surfaces inhibit bonding
Solution Approach 1:
A eutectic element powder is introduced as an intermediary substance between aluminum substrates. This powder contains elements (such as Si, Mg, Zn, Cu, or Ni) that form low-melting-point eutectic alloys with aluminum, enabling effective bonding by penetrating through the oxide film barrier and creating strong metallurgical bonds at the junctions.
Solution Approach 2:
The invention changes the chemical composition parameters of the sintering mixture by adding eutectic elements. This modifies the melting behavior and bonding characteristics of the aluminum substrates, allowing bonding to occur at lower temperatures and overcoming the oxide film resistance through eutectic liquid phase formation.
2Quantity of substance
If high porosity is achieved in porous aluminum sintered compact, then voids between substrates are maintained, but strength is further reduced
Solution Approach 1:
The invention applies local quality enhancement by concentrating eutectic element powders at the junction regions between aluminum substrates. This creates localized strong bonding zones with low-melting-point eutectic alloys precisely where needed for strength, while the bulk of the structure maintains high porosity with voids between substrates.
3Ease of manufacture
If viscous compositions are used for producing porous aluminum sintered compact, then shaping and foaming can be achieved, but production efficiency is reduced and binder removal takes long time
Solution Approach 1:
The invention extracts and eliminates the need for large amounts of binders and plasticizers from the composition. By using aluminum substrates with eutectic element powders instead of viscous compositions, the harmful binder removal step is greatly reduced, and production efficiency is improved while maintaining shaping capability.
4Ease of manufacture
If aluminum substrates are sintered with binders and plasticizers, then shaping can be achieved, but shrinkage ratios increase and dimensional accuracy deteriorates
Solution Approach 1:
The invention replaces long-living, problematic binders and plasticizers with minimal amounts of eutectic element powders that serve their bonding function and then are consumed or transformed during sintering. This eliminates the shrinkage and dimensional accuracy problems associated with traditional binder systems.
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 porous aluminum sintered compacts with high porosity, excellent dimensional accuracy, and sufficient strength, facilitating efficient and cost-effective manufacturing without the need for additional foaming steps, and allows for controlled porosity within a range of 30% to 90%.
Implementation Method 1
the eutectic element powder (23) reacts with the aluminum substrates (11) to form a low-melting-point alloy
Implementation Method 2
a junction, in which the plurality of aluminum substrates are bonded each other, includes a Ti—Al compound and a eutectic element compound
Implementation Method 3
sintering the aluminum raw material (20) held on the holder by heating
Data Source
AI summary
A high-quality porous aluminum sintered compact, which can be produced efficiently at a low cost; has an excellent dimensional accuracy with a low shrinkage ratio during sintering; and has sufficient strength, and a method of producing the porous aluminum sintered compact are provided. The porous aluminum sintered compact is the porous aluminum sintered compact that includes aluminum substrates sintered each other. The junction, in which the aluminum substrates are bonded each other, includes the Ti—Al compound and the eutectic element compound capable of eutectic reaction with Al. It is preferable that the pillar-shaped protrusions projecting toward the outside are formed on outer surfaces of the aluminum substrates, and the pillar-shaped protrusions include the junction.