Mg Copper Alloy Composition for Heat-Resistant Conductive Terminals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Copper materials used in electronic and electrical devices face challenges with insufficient heat resistance and stress relaxation resistance, particularly in high-temperature environments, and require improved electrical conductivity for high-current applications.
Innovation Solution
A copper alloy composition with controlled amounts of Mg, S, P, Se, Te, Sb, Bi, and As, along with a mechanical surface treatment, enhances electrical conductivity, heat resistance, and stress relaxation resistance, with improved resistance in the direction parallel to the rolling direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pure copper material is used to achieve high electrical conductivity, then electrical conductivity is improved, but heat resistance and stress relaxation resistance become insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of copper by adding specific amounts of Mg (0.005-0.1 mass%), Si (0.005-0.1 mass%), and other elements within controlled ranges. This compositional parameter adjustment allows the material to achieve both high electrical conductivity (97% IACS or more) and improved heat resistance, resolving the contradiction between these two properties.
Solution Approach 2:
The patent creates a composite copper alloy material by combining copper base metal with multiple alloying elements (Mg, Si, Mn, Ni, Zn, etc.). This composite structure leverages the beneficial properties of each element: Mg and Si improve strength and heat resistance, while keeping the copper matrix dominant to maintain high electrical conductivity, thus resolving the contradiction between conductivity and heat resistance.
2Reliability
If pure copper material is used to achieve high electrical conductivity, then electrical conductivity is improved, but stress relaxation resistance becomes insufficient
Solution Approach 1:
The patent adjusts compositional parameters by adding Mg (0.005-0.1 mass%) and Si (0.005-0.1 mass%) along with controlled amounts of other elements. This parameter optimization simultaneously improves stress relaxation resistance through precipitation hardening mechanisms while maintaining electrical conductivity at 97% IACS or higher, resolving the contradiction between these two reliability aspects.
Solution Approach 2:
The copper alloy forms a composite structure with Cu matrix and dispersed precipitates of Mg2Si and other intermetallic compounds. This composite microstructure provides stress relaxation resistance through the precipitate strengthening mechanism while the continuous copper matrix preserves high electrical conductivity, resolving the contradiction between stress relaxation resistance and electrical conductivity.
3Reliability
If alloying elements are added to improve heat resistance, then heat resistance is improved, but electrical conductivity decreases
Solution Approach 1:
The patent precisely controls the concentration parameters of alloying elements: Mg (0.005-0.1 mass%), Si (0.005-0.1 mass%), Mn (0.003-0.03 mass%), and other elements within specific ranges. This controlled parameter adjustment ensures that heat resistance is improved through alloying while the total impurity content remains limited (0.006 mass% or less for certain elements), preventing excessive degradation of electrical conductivity and achieving a balance where conductivity remains at 97% IACS or more.
Solution Approach 2:
The patent applies partial alloying by adding small, controlled amounts of Mg and Si (each 0.005-0.1 mass%) rather than large quantities. This partial action is sufficient to improve heat resistance through precipitation hardening while minimizing the negative impact on electrical conductivity, thus resolving the contradiction between heat resistance improvement and conductivity maintenance.
4Reliability
If alloying elements are added to improve stress relaxation resistance, then stress relaxation resistance is improved, but electrical conductivity decreases
Solution Approach 1:
The patent optimizes compositional parameters by adding Mg (0.005-0.1 mass%) and Si (0.005-0.1 mass%) which form precipitates that enhance stress relaxation resistance. The controlled low concentrations of these elements and other impurities (total 0.006 mass% or less for certain elements) ensure that electrical conductivity remains at 97% IACS or more, resolving the contradiction between stress relaxation resistance and electrical conductivity.
Solution Approach 2:
The patent creates a composite microstructure with copper matrix and finely dispersed Mg2Si precipitates. This composite structure provides stress relaxation resistance through the precipitate strengthening effect while the continuous copper matrix phase maintains high electrical conductivity, resolving the contradiction between stress relaxation resistance and electrical conductivity.
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 copper alloy achieves high electrical conductivity (97% IACS or greater), a half-softening temperature of 200°C or higher, and a residual stress ratio of 20% or greater in the rolling direction, suitable for high-current applications in high-temperature environments.
Implementation Method 1
the heat resistance and the stress relaxation resistance can be improved without greatly decreasing the electrical conductivity by dissolving Mg in a Cu matrix
Data Source
Figure 1
AI summary
This copper alloy contains greater than 10 mass ppm and 100 mass ppm or less of Mg, with a balance being Cu and inevitable impurities, in which among the inevitable impurities, a S amount is 10 mass ppm or less, a P amount is 10 mass ppm or less, a Se amount is 5 mass ppm or less, a Te amount is 5 mass ppm or less, an Sb amount is 5 mass ppm or less, a Bi amount is 5 mass ppm or less, an As amount is 5 mass ppm or less, a total amount of S, P, Se, Te, Sb, Bi, and As is 30 mass ppm or less, a mass ratio [Mg]/[S + P + Se + Te + Sb + Bi + As] is 0.6 to 50, an electrical conductivity is 97% IACS or greater, a half-softening temperature is 200°C or higher, a residual stress ratio RSG at 180°C for 30 hours in a direction parallel to a rolling direction is 20% or greater, and a ratio RSG/RSB of the residual stress ratio RSG to a residual stress ratio RSB at 180°C for 30 hours in a direction transverse to the rolling direction is greater than 1.0.