Cu-Ag Alloy Wire Microstructure for Heat-Stable Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Cu-Ag alloy wires lack sufficient strength and conductivity, particularly under high-temperature conditions due to inadequate control of the eutectic phase and insufficient optimization of manufacturing processes, leading to brittleness and reduced productivity.
Innovation Solution
A Cu-Ag alloy wire with a specific composition and metal structure, including a Cu phase as a matrix and fibrous Ag phases, controlled through precise manufacturing steps such as casting, cooling, and heat treatments to achieve a balanced ratio of fine Ag phases and grain boundary distribution, enhancing strength and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat treatment is performed to increase strength, then strength is improved, but the material becomes more brittle and thinning becomes difficult
Solution Approach 1:
The patent applies preliminary action by performing wire drawing before heat treatment to establish a fine crystalline structure, then performing heat treatment to strengthen the material without excessive brittleness. This sequence allows the material to gain strength while maintaining sufficient ductility for thinning operations.
Solution Approach 2:
The patent changes parameters by controlling heat treatment temperature and duration, and by adjusting the composition ratio of Cu and Ag, to achieve an optimal balance between strength and ductility. The specific parameter ranges are designed to prevent excessive brittleness while maximizing strength.
2Reliability
If Ag content is increased to improve conductivity, then conductivity is improved, but strength decreases
Solution Approach 1:
The patent optimizes the Ag content parameter to a specific range (1-6 mass%) and controls the particle size and distribution of Ag phases through heat treatment parameters. This parameter optimization achieves a balance where sufficient Ag provides good conductivity while the controlled microstructure maintains high strength.
Solution Approach 2:
The patent creates a composite microstructure with Cu matrix and dispersed Ag phases, where the Cu phase provides strength and the Ag phases provide conductivity. The controlled distribution and size of Ag phases within the Cu matrix achieves synergistic effects for both properties.
3Strength
If cooling rate is increased to refine crystallization, then strength is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a controlled cooling rate parameter range that achieves fine crystallization without requiring excessively complex cooling systems. The heat treatment parameters are designed to be practically implementable while achieving the desired microstructure and strength.
4Strength
If intermediate heat treatment is optimized to promote precipitation, then strength is improved, but process time increases
Solution Approach 1:
The patent optimizes heat treatment temperature and duration parameters to achieve maximum strength with minimal time. The parameter ranges are designed to achieve precipitation hardening efficiently without excessive process time, balancing quality and productivity.
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 wire maintains high strength and conductivity even under high-temperature conditions, ensuring durability and performance in electronic devices.
Implementation Method 1
a Cu-Ag alloy wire having a composition containing 1 mass% or more and 6 mass% or less of Ag and a balance of Cu and inevitable impurities, the Cu-Ag alloy wire having a metal structure including a Cu phase as a matrix and a plurality of Ag phases as a second phase
Implementation Method 2
a plurality of Ag phases as a second phase... a ratio of the number of Ag phases having a diameter D of less than 5 nm to the total number of Ag phases being 50% or more
Data Source
Figure 1
Figure 2
Figure 3(a-1)~4(c-1)
AI summary
Provided is a Cu-Ag alloy wire having sufficient conductivity and high strength and being capable of maintaining high strength even when used for a long period of time in a heat generation state. A Cu-Ag alloy wire according to the present invention is a Cu-Ag alloy wire having a composition containing 1 mass% or more and 6 mass% or less of Ag and a balance of Cu and inevitable impurities, the Cu-Ag alloy wire including a Cu phase as a matrix and a plurality of Ag phases as a second phase, the following formula (1) being satisfied with σ (µm2) being a sectional area of a cross section orthogonal to a longitudinal direction of the Cu-Ag alloy wire and D (µm) being a diameter of a true circle having an area same as each of the Ag phases present in the cross section: [Math. 1] D≦σ0.25π×10−4 in which π represents a circular constant, a ratio of the number of Ag phases having a diameter D of less than 5 nm to the total number of Ag phases being 50% or more.