Aluminum Matrix Composite Preform for High Strength and Machinability
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Solution Overview
Problem
Conventional methods for producing aluminum alloy matrix composites face challenges in achieving high strength and good processability while maintaining a ceramic and metal powder volume percentage of 50% or lower, and are hindered by issues such as low ceramic-filling rates, poor fluidity of molten metal, and increased production costs.
Innovation Solution
A high-strength metal matrix composite is produced by using a mixed powder comprising aluminum or aluminum alloy powder with a larger particle size and fine metal or ceramic powder, impregnated with molten aluminum alloy at a pressure of 20 MPa to 200 MPa, or without pressurization, to achieve a fine powder-filling rate of 10% to 50% and a flexural strength of 500 MPa to 800 MPa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional high-pressure impregnation method is used to produce aluminum alloy matrix composite, then ceramic powder can be uniformly distributed in the matrix, but the production cost increases and the process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing the ceramic powder with aluminum powder or aluminum alloy powder before infiltration. This pre-mixing step ensures uniform distribution of ceramic powder throughout the aluminum matrix without requiring complex high-pressure impregnation equipment or multi-step processes. The ceramic-containing powder mixture is directly infiltrated into the porous preform, simplifying the overall production process while maintaining uniform composition.
2Strength
If high ceramic-filling rate is achieved by conventional methods, then strength increases, but the volume percentage of ceramic and metal powder exceeds 50%, reducing processability
Solution Approach 1:
The patent applies parameter changes by controlling the volume percentage of ceramic and metal powder to be 50% or less, while achieving high strength through optimized infiltration pressure (20-200 MPa) and temperature conditions. This parameter optimization allows the composite to maintain both high strength (flexural strength ≥500 MPa) and good processability, as the moderate filler content enables easier machining with cemented carbide tools compared to high-filler composites.
3Strength
If fine powder (0.3-8 μm) is used as reinforcing material, then strength increases, but the fluidity of molten metal decreases and infiltration becomes difficult
Solution Approach 1:
The patent applies the intermediary principle by using aluminum powder or aluminum alloy powder (10-300 μm) as a mediator between the fine ceramic powder and the molten aluminum matrix. The aluminum powder in the mixed powder acts as a fluidity-enhancing agent that facilitates smooth infiltration of the molten metal into the porous preform, while the fine ceramic powder (0.3-8 μm) provides the reinforcing effect. This intermediary approach solves the contradiction between strength and infiltration speed.
4Quantity of substance
If Mg powder is added to improve wettability and infiltration, then ceramic-filling rate increases, but the production cost increases
Solution Approach 1:
The patent applies the principle of using inexpensive, readily available materials by replacing costly Mg powder with aluminum powder or aluminum alloy powder. The aluminum-based mixed powder achieves sufficient wettability and infiltration without requiring the addition of expensive reactive metals like magnesium. This substitution reduces production costs while maintaining effective ceramic-filling rates through the optimized infiltration 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 method enables the production of a high-strength composite with excellent processability, allowing for processing with cemented carbide tools and suppressing production costs, while achieving a high volume percentage of reinforcing materials.
Implementation Method 1
impregnating and filling the resulting filled body or molded body (preform) with molten aluminum or a molten aluminum alloy at a high pressure as high as a pressure of 20 MPa or higher and 200 MPa or lower
Implementation Method 2
impregnating and filling the resulting filled body or molded body (preform) with molten aluminum or a molten aluminum alloy
Data Source
Figure 1
AI summary
The present invention provides an aluminum alloy matrix composite that cannot be obtained with conventional production techniques, that has good workability while exhibiting high strength, and that makes it possible to suppress an increase in production costs, the composite having a high economically practical value. The present invention also provides a method for producing the composite. Specifically, there are provided: a high-strength metal matrix composite obtained by impregnating and filling a porous filled body or molded body (preform) with molten aluminum or a molten aluminum alloy, wherein the porous filled body or molded body (preform) is formed of a mixed powder obtained by adding at least one aluminum or aluminum alloy powder selected from the group consisting of an aluminum powder and an aluminum alloy powder each having an average particle size of 10 µm to 300 µm to at least one fine powder selected from the group consisting of a metal powder and a ceramic powder each having an average particle size of 0.3 µm to 8 µm, and the composite has a fine powder-filling rate of 10% by volume to 50% by volume and a flexural strength of 500 MPa to 800 MPa; and a method for producing the metal matrix composite.