Copper Alloy Bendability via Mg-P Composition

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Solution Overview

Problem

Copper alloys used in electronic and electric devices face challenges in maintaining excellent bendability and high yield strength, especially with varying thicknesses, as existing materials experience local elongation issues during bending processes.

Innovation Solution

A copper alloy composition with Mg between 0.5 and 3.0 mass%, P between 0.001 and 0.1 mass%, and optionally Sn between 0.1 and 2.0 mass%, undergoes specific heat treatment to enhance work-hardening rates, ensuring uniform elongation and high yield strength, even with thicker materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If copper alloy with high strength is used, then yield strength is improved, but bendability deteriorates

Engineering Contradiction:
Improve0.2% yield strengthVSAvoidbendability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies parameter changes by precisely controlling the chemical composition parameters (Mg: 0.5-3.0 mass%, P: 0.001-0.1 mass%, Sn: 0.1-2.0 mass%) and heat treatment parameters (holding temperature: 400-900°C, holding time: 1-10 hours) to achieve the desired balance between strength and bendability. The specific parameter ranges create an optimal microstructure that enables both high yield strength and excellent bendability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining multiple alloying elements (Cu-Mg-P-Sn) to form a complex alloy composition. This composite approach allows the material to exhibit both high strength and excellent bendability through synergistic effects of different elements, where Mg provides strength, P improves bendability, and Sn enhances overall performance

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If thicker copper alloy material is used, then current carrying capacity is improved, but uniform elongation deteriorates

Engineering Contradiction:
Improvematerial thicknessVSAvoiduniform elongation
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent uses parameter changes by optimizing the alloy composition (Mg: 0.5-3.0 mass%, P: 0.001-0.1 mass%, Sn: 0.1-2.0 mass%) and heat treatment parameters (temperature: 400-900°C, time: 1-10 hours) to achieve uniform elongation ≥10% even in thick materials (0.5-3.0 mm). The specific parameter ranges create a microstructure that enables uniform deformation throughout the thickness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating a specific microstructure through controlled alloying and heat treatment that provides uniform deformation characteristics throughout the material thickness. The P addition (0.001-0.1 mass%) specifically improves local deformation behavior, ensuring uniform elongation across the entire cross-section of thick materials

Inventive Principle:
Principle #3Local quality

3Strength

If Mg content is increased, then strength is improved, but conductivity deteriorates

Engineering Contradiction:
Improveyield strengthVSAvoidelectrical conductivity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the Mg content within 0.5-3.0 mass% to achieve the optimal balance between strength and conductivity. This specific parameter range ensures that the strength-enhancing effect of Mg is maximized while the conductivity-deteriorating effect is minimized through controlled concentration

Inventive Principle:
Principle #35Parameter changes

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 alloy achieves improved bendability and maintains high 0.2% yield strength, preventing significant decreases in conductivity and heat resistance, making it suitable for components like terminals and bus bars.

Implementation Method 1

undergoes specific heat treatment to enhance work-hardening rates, ensuring uniform elongation and high yield strength

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

enhance work-hardening rates, ensuring uniform elongation and high yield strength

Methodology Applied
Scientific EffectWork hardening: Plasticity

Data Source

PatentEP3348657B1Copper alloy for electronic/electrical device, component for electronic/electrical device, terminal, and bus bar
Publication Date: 2021.11.10 MITSUBISHI MATERIALS CORP
  • EP3348657B1 patent drawingFigure 1
  • EP3348657B1 patent drawingFigure 2
  • EP3348657B1 patent drawing

AI summary

Provided is a copper alloy for an electronic and electric device, including: Mg in a range of 0.5 mass% or more and 3.0 mass% or less; and a Cu balance inlcuding inevitable impurities, in which, a graph, in which a vertical axis is dσt/dεt and a horizontal axis is a true strain εt, dσt/dεt being defined by a true stress σt and the true strain εt, obtained in a tensile test of the copper alloy, has a strained region that has a positive slope of dσt/dεt.