Copper Alloy Sheet Crystal Texture Control for Bending and Strength
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Solution Overview
Problem
Existing copper alloy sheet materials used in automotive and electronic components face challenges with bending properties, mechanical strength, and electrical conductivity, particularly due to limitations in controlling crystal orientations and the trade-off between these properties, leading to cracks and reduced contact pressure.
Innovation Solution
A copper alloy sheet material with a specific crystal texture composition, characterized by a predetermined area ratio of BR, RDW, cube, copper, S, and brass orientations, along with controlled additive elements, is developed to enhance bending properties and mechanical strength while maintaining electrical conductivity, through a method involving casting, homogenization, hot-rolling, cold-rolling, heat treatments, and aging precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the mechanical strength of copper alloy sheet material is enhanced, then the proof stress increases, but the bending property deteriorates and cracks occur
Solution Approach 1:
The patent applies parameter changes by precisely controlling crystal orientation parameters (X-ray diffraction intensities of specific planes) and alloy composition parameters (Ni, Co, Si content ratios) to achieve optimal balance between proof stress and bending property. The specified intensity ratios and compositional ranges resolve the contradiction by transforming the material's microstructural parameters.
Solution Approach 2:
The patent creates a composite microstructure by combining multiple crystal orientations ({200}, {220}, {311}, {420} planes) in specific intensity ratios, along with controlled alloying elements (Ni, Co, Si), to achieve a material that simultaneously exhibits high strength and good bending properties through synergistic effects of different phases and orientations.
2Volume of moving object
If the size of terminal or contact part is reduced, then the weight and size decrease, but the bending radius decreases and cracks occur more easily
Solution Approach 1:
The patent resolves the size-bending contradiction by changing the material's crystal orientation parameters and compositional parameters, which improve the material's inherent bending resistance. This allows smaller terminals to maintain adequate bending properties through optimized microstructure rather than increasing size.
3Reliability
If cracks occur at bent portion, then the contact pressure decreases, but the electrical connection is insulated and function is lost
Solution Approach 1:
The patent applies preliminary anti-action by pre-optimizing the crystal orientation and alloy composition to prevent crack formation before it occurs. The controlled intensity ratios of crystal planes and specific alloy content ranges create a material structure that inherently resists crack initiation and propagation during bending, thereby protecting electrical connection reliability.
4Weight of moving object
If the thickness of substrate material is reduced, then the weight decreases, but the mechanical strength decreases
Solution Approach 1:
The patent resolves the thickness-strength contradiction by changing the material's compositional parameters (alloying elements) and microstructural parameters (crystal orientation intensities). These parameter optimizations enhance the material's intrinsic strength properties, allowing thinner substrates to maintain adequate mechanical strength through improved material quality rather than increased thickness.
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 solution achieves excellent bending properties, mechanical strength, and stress relaxation resistance, reducing cracks and maintaining high electrical conductivity, making it suitable for connectors and other electronic components.
Implementation Method 1
homogenization heat treatment
Implementation Method 2
hot-rolling, cold-rolling
Implementation Method 3
heat treatment
Implementation Method 4
aging precipitation heat treatment
Implementation Method 5
X-ray diffraction intensities
Implementation Method 6
X-ray diffraction intensities obtained from crystal planes
Data Source
Figure 1(a)~2
AI summary
{Problems} To provide a copper alloy sheet material, which is excellent in the bending property, and has an excellent mechanical strength, and which is thus suitable for lead frames, connectors, terminal materials, and the like, for electrical/electronic equipments, for connectors, for example, to be mounted on automotive vehicles, and for terminal materials, relays, switches, and the like; and to provide a production method of the same. {Means to solve} A copper alloy sheet material, having an R value of 1 or greater, which is defined by: R=BR+RDW+W/C+S+B wherein [BR], [RDW], [W], [C], [S], and [B] represent an area ratio of crystal texture orientation component of BR orientation {3 6 2} <8 5 3>, RD-rotated-cube orientation {0 1 2} <1 0 0>, cube orientation {1 0 0} <0 0 1>, copper orientation {1 2 1} <1 1 1>, S-orientation {2 3 1} <3 4 6>, and brass orientation {1 1 0} <1 1 2>, respectively, in crystal orientation analysis in an EBSD (electron back scatter diffraction) analysis, and having a proof stress of 500 MPa or greater, and an electrical conductivity of 30%IACS or higher; and a production method of the same.