Cu-Co-Si Alloy Strip Multi-Stage Aging Suppresses Hanging Curl
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cu-Co-Si-based copper alloys for electronic components face challenges in achieving a balance of high strength, electrical conductivity, and spring bending elastic limit, while also experiencing issues with shape accuracy and hanging curl during industrial-scale strip production, particularly due to batch furnace aging treatments that lead to curling and reduced dimension stability.
Innovation Solution
A Cu-Co-Si-based alloy strip is produced through a method involving solution treatment followed by multi-stage aging treatment under specific temperature and time conditions, with cold rolling and thermal refining annealing, which suppresses hanging curl and enhances strength, electrical conductivity, and spring bending elastic limit, and is characterized by a diffraction intensity ratio and composition within defined ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch furnace aging treatment is used for industrial-scale production, then production efficiency is improved, but hanging curl occurs and shape accuracy deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the single-stage aging treatment into multiple stages with different temperature conditions. The first aging treatment uses a higher temperature (400-500°C) to achieve rapid precipitation hardening, while the second aging treatment uses a lower temperature (200-400°C) to refine the precipitate distribution and reduce internal stresses. This multi-stage approach segments the heat treatment process to simultaneously achieve high productivity through efficient hardening and high shape accuracy through stress reduction and curl suppression.
2Strength
If aging treatment is conducted to increase strength, then mechanical strength is improved, but spring bending elastic limit may be compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the temperature and time parameters of the aging treatment. The first aging treatment operates at 400-500°C for 1-24 hours to achieve significant strength increase through precipitate formation. The second aging treatment operates at 200-400°C for 1-24 hours to adjust the precipitate distribution and reduce internal stresses. By changing the temperature parameter between stages, the patent achieves both high mechanical strength and high spring bending elastic limit, with the alloy exhibiting 0.2% offset tensile strength of 500-800 MPa and spring bending elastic limit of 300-500 MPa.
3Reliability
If Cu-Co-Si alloy composition is used instead of Cu-Ni-Si alloy, then electrical conductivity is improved, but spring bending elastic limit is insufficient
Solution Approach 1:
The patent applies composite materials by creating a dual-phase microstructure consisting of a copper matrix with dispersed Co-Si intermetallic precipitates. The copper matrix provides high electrical conductivity (50-80% IACS), while the Co-Si precipitates provide strengthening and improve spring bending elastic limit. The controlled precipitation of fine Co-Si particles during the two-stage aging treatment creates a composite structure that combines the electrical conductivity benefits of Cu-Co-Si alloy with the mechanical properties needed for high spring bending elastic limit.
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 method results in a Cu-Co-Si-based alloy strip with improved balance of strength, electrical conductivity, and spring bending elastic limit, while effectively controlling hanging curl, ensuring enhanced shape accuracy and stability during press working.
Implementation Method 1
a supersaturated solid solution, which has been subjected to solution treatment
Implementation Method 2
subjected to ageing treatment, whereby fine precipitates are homogeneously dispersed and not only the strength but also the electrical conductivity of the alloy are increased
Implementation Method 3
performing solution treatment at 950-1050°C, and then cooling the material temperature with an average cooling rate of at least 15°C/sec from 850°C to 400°C
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Cu-Co-Si-based alloy strip, which has not only an excellent balance between strength and electrical conductivity but also suppressed hanging curl, is provided. The copper alloy strip for electronic materials comprises 0.5-2.5 mass% of Co, 0.1-0.7 mass% of Si, the balance Cu and inevitable impurities, wherein, from a result obtained from measurement of an X ray diffraction pole figure, using a rolled surface as a reference plane, the following (a) is satisfied. (a) A diffraction peak height at ß angle 120° among diffraction peak intensities by ß scanning at α=25° in a {200} pole figure is at least 10 times that of standard copper powder.