Aluminum Alloy Wire Surface Void Control for Fatigue Resistance
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Solution Overview
Problem
Aluminum alloy wires used in electrical wires face challenges in impact resistance and fatigue characteristics, particularly when subjected to repeated bending and impact, leading to potential disconnection.
Innovation Solution
An aluminum alloy wire with a specific composition containing 0.005-2.2% Fe, subjected to softening treatment, and having a surface layer with a minimal amount of voids, is developed. This wire has a wire diameter of 0.2-3.6 mm, tensile strength of 110-200 MPa, 0.2% proof stress of 40 MPa, breaking elongation of 10%, and electrical conductivity of 55% IACS, enhancing its impact resistance and fatigue characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum alloy wire is subjected to softening treatment to improve toughness and electrical conductivity, then breaking elongation and electrical conductivity are improved, but tensile strength decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Fe content within 0.005-2.2 mass% and controlling the total cross-sectional area of voids in the surface layer to 2 μm² or less. This optimization of compositional and structural parameters achieves a balance between strength and reliability, allowing the wire to meet both tensile strength requirements and impact resistance requirements after softening treatment.
2Strength
If aluminum alloy wire contains higher Fe content to improve strength, then tensile strength is improved, but electrical conductivity deteriorates
Solution Approach 1:
The patent optimizes the Fe content parameter within the specific range of 0.005-2.2 mass% to achieve the desired balance between strength and electrical conductivity. This controlled parameter change ensures that the wire maintains adequate electrical conductivity (equal to or more than 55% IACS) while achieving the required tensile strength (equal to or more than 110 MPa).
Solution Approach 2:
The patent creates a composite structure by controlling the distribution and size of voids in the surface layer (total cross-sectional area equal to or less than 2 μm² within a 30 μm × 50 μm measurement region). This controlled composite structure with Fe-containing aluminum alloy matrix and minimized voids achieves improved strength while maintaining electrical conductivity through the softening treatment.
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 aluminum alloy wire exhibits improved impact resistance and fatigue characteristics, reducing the likelihood of disconnection due to its high strength, toughness, and minimal voids, which act as cracking origins, while maintaining high electrical conductivity.
Implementation Method 1
the aluminum alloy wire is softened so as to have high strength, high toughness and high electrical conductivity
Data Source
AI summary
An aluminum alloy contains equal to or more than 0.005 mass % and equal to or less than 2.2 mass % of Fe, and a remainder of Al and an inevitable impurity. In a transverse section of the aluminum alloy wire, a surface-layer void measurement region in a shape of a rectangle having a short side length of 30 μm and a long side length of 50 μm is defined within a surface layer region extending from a surface of the aluminum alloy wire by 30 μm in a depth direction, and a total cross-sectional area of voids in the surface-layer void measurement region is equal to or less than 2 μm2.