Nano-grained Multilayer Copper Alloy Sheet for High Strength and Conductivity
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Solution Overview
Problem
Existing methods for manufacturing copper alloy sheets with high strength and electrical conductivity face limitations, as increasing alloy content to enhance strength compromises rollability and electrical conductivity, and existing accumulative roll-bonding methods struggle to achieve uniform thickness and effective crystalline grain micronization, leading to reduced quality and conductivity.
Innovation Solution
The method involves alternately overlapping and roll-bonding oxygen-free copper (OFC) and deoxidized low-phosphorous copper (DLP) alloy layers, with surface treatment including degreasing and wire brushing, to achieve a multi-layer copper alloy sheet with electrical conductivity of 85 IACS (%) or more and tensile strength of 500 MPa or more through repeated accumulative roll-bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If alloy content is increased to improve strength, then tensile strength is improved, but electrical conductivity and rollability deteriorate
Solution Approach 1:
The copper alloy sheet is divided into multiple layers with different compositions (OFC layer and DLP layer) stacked alternately. The OFC layer provides high electrical conductivity while the DLP layer provides high strength. By segmenting the homogeneous material into heterogeneous layers, the patent achieves both high strength and high electrical conductivity simultaneously, resolving the contradiction between strength and conductivity.
Solution Approach 2:
The patent creates a composite material structure by combining oxygen-free copper (OFC) and deoxidized low-phosphorous copper (DLP) in alternating layers. This composite structure allows each layer to contribute its superior properties (OFC for conductivity, DLP for strength) to the overall material, achieving a balance between strength and electrical conductivity that cannot be obtained in homogeneous alloys.
2Strength
If processing amount is increased to micronize crystalline grain, then strength is improved, but shape (cross sectional area) is inevitably changed
Solution Approach 1:
Surface treatment (degreasing and wire brushing) is performed preliminarily before roll-bonding to prepare the sheet surfaces for effective bonding. This preliminary action ensures proper adhesion between layers during the accumulative roll-bonding process, enabling the shape change required for grain micronization while maintaining dimensional control and preventing defects.
Solution Approach 2:
The patent uses accumulative roll-bonding to deform the material in a controlled manner through repeated cycling, achieving grain refinement without significant lateral shape change. The process exploits the thickness dimension for accumulation of deformation while maintaining the width and length dimensions relatively stable, thus micronizing grains without inevitable shape distortion.
3Strength
If accumulative roll-bonding is performed to achieve crystalline grain micronization, then strength is improved, but uniform thickness and sheet quality are compromised
Solution Approach 1:
Surface treatment including degreasing and wire brushing is performed preliminarily to prepare the sheet surfaces for effective bonding. This ensures proper adhesion between layers during roll-bonding, preventing defects and maintaining uniform thickness throughout the multi-layer structure, thus preserving manufacturing precision while achieving grain refinement.
Solution Approach 2:
The patent carefully controls processing parameters including roll-bonding temperature, pressure, and number of cycles to achieve grain refinement while maintaining uniform thickness. By optimizing these parameters, the process achieves nanocrystalline grain structure for high strength while preserving sheet quality and dimensional uniformity.
4Strength
If high-strength copper alloy sheets are accumulated and roll-bonded to increase strength, then tensile strength is improved, but cracks occur and sheets fail to bond
Solution Approach 1:
Surface treatment (degreasing and wire brushing) is performed preliminarily to clean and activate the sheet surfaces before bonding. This preliminary action removes contaminants and creates a surface condition that promotes strong adhesion during roll-bonding, preventing crack formation and ensuring reliable bonding between layers even under high deformation conditions.
Solution Approach 2:
The patent optimizes processing parameters including temperature, pressure, and deformation rate during accumulative roll-bonding to prevent crack formation while achieving high strength. By carefully controlling these parameters, the process maintains sheet integrity and bonding quality throughout the multi-pass deformation required for grain refinement.
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
This approach results in high strength and high electrical conductive nano crystalline grain multi-layer copper alloy sheets with improved uniformity and enhanced properties, overcoming the limitations of existing methods by achieving both high strength and conductivity while maintaining sheet quality.
Implementation Method 1
a copper alloy sheet having high strength and electrical conductivity, the copper alloy sheet has been manufactured by rolling a copper alloy manufactured by adding an alloy element to increase the strength by rolling
Implementation Method 2
An accumulative roll-bonding (ARB) method is one of severe plastic deformation methods that improve a mechanical characteristic by ultra-micronizing a crystalline grain level of a metallic material up to a submicron range
Data Source
AI summary
In a high strength and high electrical conductive nano crystalline grain multi-layer copper alloy sheet, a plurality of high strength and high electrical conductive nano crystalline grain multi-layer sheets manufactured by roll-bonding an oxygen free copper (OFC) alloy sheet and a deoxidized low-phosphorous copper (DLP) alloy sheet are plastically bonded by roll-bonding method so that an OFC alloy layer and a DLP alloy layer are alternated to each other to have electrical conductivity of 85 IACS (%) or more and tensile strength of 500 MPa or more.