Copper Alloy Wire with Recrystallized Texture for Magnet Wires

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current copper alloy wires face challenges in achieving a balance between elongation and physical strength, particularly for extra-fine wires with diameters of 0.07 mm or less, while also requiring enhanced resistance to bending fatigue and coil formability, which is difficult to achieve with existing high-concentration Cu-Ag alloys due to their high cost and limited electrical conductivity.

Innovation Solution

A copper alloy wire with a recrystallized texture, composed of 0.1 to 4 mass% Ag and 0.05 to 0.30 mass% of elements like Sn, Mg, Zn, In, Ni, Co, or Cr, with a specific crystal orientation and grain size, is produced through a method involving cold-working and annealing processes to achieve high tensile strength and elongation, suitable for magnet wires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If pure copper is used to achieve high elongation and toughness, then coil formability is improved, but physical strength and resistance to fatigue are lowered

Engineering Contradiction:
Improvecoil formabilityVSAvoidphysical strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent uses composite material by combining copper with small amounts of alloying elements (0.01-3 mass% of at least one element selected from Ag, Au, Al, Co, Cr, Fe, In, Mg, Mn, Mo, Ni, Pb, Pd, Pt, Si, Sn, Ti, Zn, and Zr) to create a material that exhibits both high elongation and high physical strength, resolving the contradiction between formability and strength

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the compositional parameters by precisely controlling the alloying element content within specific ranges (0.01-3 mass%) and the crystallite size within 1-10 nm range, achieving optimal balance between elongation and physical strength through parameter optimization

Inventive Principle:
Principle #35Parameter changes

2Strength

If high-concentration Cu-Ag alloy is used to enhance tensile strength, then physical strength is improved, but electrical conductivity is lowered

Engineering Contradiction:
Improvetensile strengthVSAvoidelectrical conductivity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes the concentration parameter by limiting alloying elements to a small range (0.01-3 mass%) and selecting from multiple element options, achieving sufficient tensile strength enhancement while minimizing the impact on electrical conductivity through precise compositional control

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material strategy by creating a copper-based alloy system with trace amounts of strengthening elements, where the base copper matrix maintains high electrical conductivity while the dispersed alloying elements provide tensile strength enhancement

Inventive Principle:
Principle #40Composite materials

3Length of moving object

If wire diameter is reduced to achieve extra-fine wire, then miniaturization is improved, but attainment of elongation becomes more difficult

Engineering Contradiction:
Improvewire diameterVSAvoidelongation
Core Design Contradiction:
Length of moving objectVSEase of operation

Solution Approach 1:

The patent changes the microstructural parameter by controlling crystallite size to an ultra-fine range of 1-10 nm, which fundamentally alters the deformation behavior of the material, enabling extra-fine wires to achieve high elongation (30% or more) that would be impossible with conventional microstructures

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material approach by creating a nanoscale copper alloy composite where the interaction between copper matrix and alloying elements at the nanoscale level produces synergistic effects that simultaneously enable miniaturization and maintain high elongation

Inventive Principle:
Principle #40Composite materials

4Strength

If working degree is increased to enhance tensile strength, then physical strength is improved, but elongation is lowered

Engineering Contradiction:
Improvetensile strengthVSAvoidelongation
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the microstructural parameter by controlling crystallite size to 1-10 nm range, which fundamentally alters the strength-elongation relationship, allowing the material to achieve high tensile strength (200 MPa or more) while maintaining high elongation (30% or more) that would normally be mutually exclusive

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material strategy where the nanoscale copper alloy composite structure provides both strength and ductility through the interaction of copper matrix with dispersed alloying elements, breaking the conventional trade-off between tensile strength and elongation

Inventive Principle:
Principle #40Composite materials

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 resulting copper alloy wire exhibits excellent coil characteristics, including resistance to bending fatigue and formability, while maintaining high electrical conductivity, making it suitable for use in magnet wires at a lower cost.

Implementation Method 1

the copper alloy wire has a recrystallized texture... produced through a method involving cold-working and annealing processes

Methodology Applied
Scientific EffectRecrystallization: Annealing

Data Source

PatentEP3128019B1Copper alloy wire material and manufacturing method thereof
Publication Date: 2020.10.14 FURUKAWA ELECTRIC CO LTD
  • EP3128019B1 patent drawingFigure 1
  • EP3128019B1 patent drawingFigure 2

AI summary

{Problem} To provide, at low cost, a copper alloy wire that has high in elongation and that is excellent in workability, i.e. coil formability, and in addition to those, that is also excellent in coil characteristics (service life of the coil), which is obtained by using the copper alloy wire, and that is used, for example, in magnet wires. {Solution means} A copper alloy wire containing 0.1 to 4.0 mass% of Ag, and/or at least one selected from the group consisting of Sn, Mg, Zn, In, Ni, Co, Zr and Cr each at a content of 0.05 to 0.30 mass%, with the balance being Cu and unavoidable impurities, wherein when a cross-section perpendicular to the longitudinal direction of the wire is observed by EBSD in a direction normal to the cross-section, the area ratio of grains having <101> direction is 10% or more of the entire measurement area; and a method of producing the copper alloy wire.