At the 2024 (19th) SMM Copper Conference and Copper Industry Expo - Electrical Power Transmission and Distribution Forum jointly organized by Shanghai Nonferrous Metals Network (SMM) and Shandong Hengbang Smelting Co., Ltd., Professor/Doctoral Supervisor Gong Shen of Central South University interpreted the basic research on the application of new high-strength and high-conductivity copper alloys.
Product quality is in line with international standards and comprehensive strength is strong: good quality, the quality standards of major products are in line with international standards; the industrial chain is complete, and all kinds of copper products can be produced independently; net exports are expanding year by year, and international competitiveness is enhanced; supporting cooperation is perfect, and the supply chain advantages are obvious.
High performance copper alloy design
Design principles
Adjust material composition: that is, add alloy elements to copper to improve the performance of the material, that is, research and develop new copper alloy materials; adjust the organizational structure through heat treatment: carry out reasonable heat treatment to adjust the organizational structure of the material and improve the performance of the material; simple design + special processing technology: through processing technology instead of adding alloy elements; direct value preservation and recycling: such as coating elements are effective alloying elements, C18045.
The design method is also introduced.
Copper alloy for integrated circuit lead frames
Copper alloy for integrated circuit lead frames
The main function of the lead frame copper alloy is to provide a carrier for mechanical support of the chip and to serve as an electrically conductive and thermally conductive medium. On the one hand, it connects the chip/device circuit to form an electrical signal path, and on the other hand, it dissipates heat outwards together with the package shell to form a heat dissipation path.
The development trend of integrated circuits: from small scale to medium scale, large scale, ultra-large scale, extra-large scale, and finally to large scale.
Lead frame: It is the carrier of the chip and an important component of the integrated circuit.
Lead frame development: multi-pin, high-density, ultra-thin, miniaturized Lead frame materials: high strength, high elasticity, high conductivity, high softening temperature resistance, high precision, high surface quality
Lead frame processing method: from traditional physical stamping to etching forming
Service conditions: Integrated circuits are developing towards high integration, high flow capacity, and high reliability, and wiring is becoming more sophisticated.
Main performance requirements of etching frame copper alloy
It describes the main performance requirements of etching frame copper alloy from the perspective of organizational structure characteristics, intrinsic properties, form and position tolerances, post-processing properties, and plating properties.
Residual Stress Control of Copper Alloy for Integrated Circuit Lead Frames
In the process of strip processing, uneven deformation is bound to exist. How to control the macroscopic plate shape during the rolling process is one of the core technologies of etched copper strip processing.
How to better improve the plate shape, reduce residual stress and improve the uneven distribution of residual stress during the post-processing process of the strip is one of the etching type copper strip processing technologies.
The submicron control of the primary solidification structure and the nano-dispersion control technology of the precipitated phase are the key to achieving low burrs, protrusions and good bending properties after etching.
Key technologies for residual stress control of strip.
By adjusting the roller convexity, roller surface quality, stretch straightening + annealing process, etc. during the cold rolling process, the residual stress, etching performance and offline shape and position tolerance of the strip can be improved.
The performance of several lead frame materials, including C194 lead frame material (Cu-Fe-P alloy, high comprehensive performance), high-strength and high-conductivity alloy (represented by Cu-Cr-Zr alloy), and high-strength and medium-conductivity alloy (represented by Cu-Ni-(Co)-Si alloy).
Non-vacuum melting of large-sized Cu-Cr-Zr alloy ingots
Problem: Zr is easily oxidized to form slag and react with furnace lining materials, making it difficult to control the stable composition.
Measures: melt pretreatment, copper-zirconium master alloy addition, casting process regulation, slag-gas combined protection, pouring pipe and runner design and protection.
It also introduces the aging precipitation characteristics of CuCr alloys, the processing flow of C7025 alloy, typical processing parameters of C7025 alloy, the impact of changes in Ni and Si on performance, and phase changes of alloys.
Rolled copper foil for printed circuit boards and IGBTs
High-performance copper foil for printed circuit board copper clad laminates
Printed Circuit Board (PCB), PCB is a key component supporting the development of 5G technology. It is a collection of systems carried by each electronic product. PCB is mainly composed of two types of materials: insulating substrate and conductor. It plays a supporting and interconnecting role in electronic equipment and is called the "mother of electronic products."
Copper Clad Laminate (CCL) is the core substrate for manufacturing printed circuit boards (PCBs). Copper Clad Laminate accounts for 30%-40% of the entire PCB production cost. It is responsible for the (PCB) conductive and supporting functions.
Copper foil: It is a key material for manufacturing copper-clad laminates. It is required to have high conductivity and good weldability. There must be no scratches, sand holes or wrinkles on the surface of the copper foil. The thinner it is, the easier it is to etch, and the more suitable it is for manufacturing high-density printed circuit boards with complex circuits.
Copper foil: divided into rolled copper foil and electrolytic copper foil
Specific requirements of 5G for copper foil materials: excellent thin lines/bending, low recrystallization temperature; small dielectric constant and dielectric loss; poor electromagnetic wave coverage, strong electromagnetic shielding ability of materials; copper clad laminates develop in the direction of multiple layers, thinner foil thickness, and higher bending performance; based on the skin effect, the skin depth becomes shallower at high frequencies, resulting in a smaller flow cross-sectional area and increased AC resistance (skin resistivity at 10GHz is 3 times that of 1GHz), and the copper foil roughness is required to be as low as possible, and the smaller the roughness, the smaller the dielectric loss.
Rolled copper foil
Rolled copper foil: smart wearables, 5G&6G high-speed communications, new energy vehicles, VR/AR, AI and other industries.
Requirements for the transmission properties and flexibility of rolled copper foil.
When the oxygen content in the copper matrix reaches a certain level, the surface defects and roughness are lower, making it more suitable for the transmission of higher frequency signals.
The key to the preparation of high-flexibility oxygen-rich copper rolled foil products for high-speed communications is the production of high-quality oxygen-rich copper foil base material.
The maximum solid solubility of oxygen in solid copper is about 80ppm. When it exceeds 80ppm, oxygen exists in the form of Cu2O. When the oxygen content exceeds a certain amount, it is distributed at the grain boundary in the form of Cu+Cu2O. When the oxygen content reaches the eutectic composition point of 0.39wt%, all of them are eutectic structures.
The dissolved amounts of hydrogen and oxygen in the copper liquid are inversely proportional. As the dissolved amount of oxygen increases, the dissolved amount of hydrogen decreases. Therefore, when preparing oxygen-enriched copper ingots, the absorption of hydrogen must be strictly controlled to prevent defects such as pores from forming in the ingot, which in turn leads to pinhole defects in the foil.
It also introduces the factors affecting oxygen content, process parameters for regulating oxygen content, the microscopic action mechanism of trace elements in alloys, and copper foil rolling process control.
New rolled copper alloy foil
Oxygen copper foil, with an oxygen content of 150-500PPM, is also called brittle copper foil, with high strength and good surface quality.
Oxygen-free copper foil, the lower the impurity elements, the better, the conductivity can reach 101-103% IACS, low strength and good toughness.
Copper foil for IGBT
It explains the high heat-resistant oxygen-free copper preparation technology (DBC) for GBT.
Copper alloys for new energy vehicles
Copper alloys for new energy vehicles
Traditional automobile internal combustion engines use 23kg of copper, hybrid electric vehicles use 40kg of copper, plug-in hybrid electric vehicles use 60kg of copper, pure electric vehicles use 111kg of copper, and pure electric buses use 224-369kg of copper depending on the battery capacity.
According to IDTechEx data, the amount of copper used in new energy vehicles is: batteries account for about 48%, motors account for about 12%, high-voltage wiring harnesses account for about 6%, low-voltage wiring harnesses account for about 28%, and others account for 6%;
Each new energy vehicle uses about 23kg of copper in low-voltage wiring harnesses and about 5kg of copper in high-voltage wiring harnesses. In the low-voltage wiring harness system, low-voltage cables (generally using oxygen-free copper wire) account for about 85% of the copper, and low-voltage connectors (generally using copper strips, C192, etc.) account for about 15% of the copper.
In the high-voltage wiring harness system, the copper content of high-voltage cables (using annealed pure copper) accounts for about 75%, and the copper content of high-voltage connectors (using phosphor bronze, beryllium bronze, copper-chromium-zirconium, copper-nickel-silicon, C194 and other copper alloys) accounts for about 15%. According to calculations, the copper content of low-voltage cables of a single vehicle is about 19.8kg, the copper content of low-voltage connectors of a single vehicle is about 3.49kg, the copper content of high-voltage cables of a single vehicle is about 3.7kg, and the copper content of high-voltage connectors of a single vehicle is about 0.75kg.
Copper rod for driving motor
Drive motor: The copper rod consumption of a bicycle is about 14 kg
The drive motor is the power source of electric vehicles, and its key components are the stator and rotor.
Permanent magnet synchronous motors and AC asynchronous motors have become the mainstream choices in the passenger car field.
Permanent magnet synchronous motors have the advantages of high torque density, power density, high efficiency and good speed regulation performance. Permanent magnet synchronous motors account for over 94% of the domestic drive motor market.
Since 2021, Tesla and GAC have replaced their vehicles with flat wire motors, BYD's entire DMI series uses flat wire motors, and SAIC and Great Wall's new models have also switched to flat wire motors, with a market share of more than 23.9%.
Domestic manufacturers include Jingda Co., Ltd., Jinbei Electric, Jintian Copper Industry and Great Wall Technology.
Oxygen-free copper rods (oxygen content less than 10ppm) are used for processing, and most of the oxygen-free copper rods are purchased from outside.
High purity, excellent electrical conductivity, thermal conductivity, cutting performance and good welding performance, no "hydrogen disease" or less "hydrogen disease".
Copper alloy for new energy vehicle connector terminals
Automotive connectors are signal hubs that connect various electronic systems and are used in various subsystems, including power systems, body systems, information control systems, safety systems, and on-board equipment. A traditional fuel vehicle uses about 500 connectors, while a new energy vehicle will use 800-1000 connectors, accounting for 45%-65% of the cost of the new energy vehicle.
New energy vehicles mainly have two energy replenishment modes: charging and battery replacement. The carriers of these two energy replenishment modes are charging piles and battery replacement stations. The electrical connectors and battery replacement connectors used are both high-voltage connectors. Different from the charging mode of charging piles, battery replacement is to store and charge a large number of batteries in a centralized charging station, and directly replace the batteries of electric vehicles in the battery distribution station.
Copper alloy is used in connector terminals, accounting for about 26.4% of its total cost. The choice of electroplating materials is mainly gold plating, tin plating, nickel plating and silver plating.
Copper alloy for high-speed rail contact wire
Copper alloy for high-speed rail contact wire
The contact network includes contact wires, load-bearing cables, suspension strings, etc.
The contact wire is the most important component. When the electric locomotive is running, its pantograph slide directly rubs against the contact wire and obtains electrical energy.
The function of the catenary is to suspend the contact wire and at the same time carry a certain current to reduce the impedance of the traction network, reduce voltage loss and energy consumption.
The dropper is the connecting wire between the contact wire and the load-bearing cable.
The through ground wire is a grounding conductor that connects the traction power supply return, power supply, signal, communication and other electronic information systems, and various equipment along the railway to form an equipotential connection, thereby realizing the functions of protecting the equipment along the railway from electromagnetic induction interference, electrostatic interference, and lightning intrusion.
Shock wave velocity (speed of transmission of contact wire fluctuations).
Feasible measures: Improve the tensile strength of the contact line to ensure that the tension of the contact line is increased while meeting the safety factor.
The current status and development trend of domestic and foreign research on contact wires for electrified railways: The comparison of the main technical indicators of contact wires at home and abroad, the tensile strength and conductivity of several copper alloy contact wires are introduced. In addition, the comprehensive performance of Japan's PHC contact wire is excellent, which blocks China's technology. No relevant preparation technology data is seen.
The Cu-Mg contact wire and its production process are described.
The strengthening and heat resistance mechanism of Cu-Cr-Zr alloys was explored, and the existence form of Zr element in the alloy and its influence on the nucleation and growth of nano-Cr strengthening phase were explained.
A theoretical framework for multi-scale and multi-dimensional design and preparation of Cu-Cr alloys is proposed.
The Zr element is easily oxidized and slag-forming, and is easy to react with the furnace lining material. It forms complexes with trace amounts of oxides in the melt, causing changes in the melt viscosity and making continuous casting difficult.
Alloy melt pretreatment, optimization of copper-zirconium master alloy addition, slag-gas joint protection, and casting process regulation (core parameters: casting temperature, casting stop ratio, etc.) are used to achieve non-vacuum continuous casting of CuCrZr alloy and semi-continuous casting of large billets. Uniform distribution of Zr is achieved: Zr: 0.02-0.1wt%.
Secondary cold rolling aging can effectively improve the alloy properties, with the strength reaching above 620MPa, the electrical conductivity reaching 82%IACS, and the softening temperature reaching 550℃.
Ultra-high strength elastic copper alloy
Preparation process of ultra-high strength CuNiSn alloy
Cu-Ni-Sn alloy is a copper alloy material with high strength, high toughness, excellent wear resistance and corrosion resistance: the strength of Cu-15Ni-8Sn alloy can reach up to 1350MPa and the conductivity is 8%IACS; the strength of Cu-9Ni-6Sn alloy can reach up to 1000MPa and the conductivity is 12%IACS.
Microstructure and Properties of Cu-Ti Alloy
As an ultra-high-strength elastic copper alloy, Cu-Ti alloys have high elasticity, fatigue resistance, non-magnetic, no impact sparks, easy electroplating and brazing, wear resistance and excellent bending performance (small r/t); they are widely used in conductive elastic elements such as connectors, switch contacts and springs for transmitting power signals.
Development trend of copper alloy
Copper material carbon reduction processing technology
The implementation paths for carbon emission reduction in the copper industry mainly include: application of low-carbon raw materials, promotion and development of low-carbon processes, and optimization of low-carbon energy structure.



(1) Application of low-carbon raw materials and recycling of waste copper alloys (urban mines)
Accurate sorting of scrap copper, removal and reduction of harmful impurity elements in scrap copper; research and development of efficient slag-making agents, refining agents, etc. in the scrap copper smelting process; development of efficient melting furnaces, and development of recycled copper alloys with good comprehensive performance using scrap copper.
Develop same-grade recycling technologies for key products such as brass, copper, lead frames and nickel silver;
A complete recycling system has been established so that all copper alloy materials can enter the recycling system after their service life and be used at the same level or upgraded.
(2) Green intelligent manufacturing technology of copper alloy
High-efficiency and low-energy casting, high-efficiency heat treatment and processing technology.
(1) Copper alloy multi-stream and multi-head high-efficiency melting and casting technology and submerged liquid transfer casting technology;
(2) Combustion control technology, flue gas waste heat utilization technology and computer control technology.
(3) Large-size ingot high-speed hot deformation equipment and technology and strong cold plastic deformation technology to increase production capacity and reduce material geometric loss.
Establish advanced short-process production lines to realize the industrial production of high-end copper-based alloy products, such as copper alloy plates and strips for integrated circuit lead frames, contact network cables, bonding wire copper alloys, micromotor ultrafine wires, and white copper alloy pipes for marine engineering.
Establish a fully coupled simulation technology for the entire copper alloy preparation process to achieve rapid optimization of production process parameters. Form intelligent production, logistics, and warehousing technologies based on the Industrial Internet of Things to achieve intelligent manufacturing across the entire industry chain.
(3) Digital technology for copper material design
Digital alloying technology realizes rational design of alloys from composition design to process design and efficient experiments.
Alloy composition design is the source of development. Thermodynamics, kinetics and phase field calculation methods are used to design the theoretically optimal alloy composition and predict the target performance of the alloy, reducing trial and error.
High-throughput experimental technology achieves the most efficient trial production at the lowest cost and energy consumption, thereby determining the optimal composition design of the product;
Finite element technology is used to optimize the design of tooling and dies during melting, heat treatment and processing, optimize the design of production process parameters, and quickly and accurately determine the alloy production process.
Copper alloy processing full process efficient processing technology
High-efficiency melting and casting technology for copper alloys: multi-stream and multi-head casting and submerged liquid transfer casting technology.
Energy-saving walking furnace heating technology: By adjusting the stepping speed and spacing of the large copper processing walking furnace, the heating quality of the ingot is controlled to further improve the heating efficiency.
Strong deformation and high-efficiency hot deformation technology: combustion control technology, flue gas waste heat utilization technology, etc. to improve the utilization rate of thermal energy; large-size ingot high-speed deformation hot rolling equipment and process, to achieve high-speed deformation hot processing technology with large production capacity and low material geometric loss; high-speed deformation increases the final rolling temperature of the strip, reduces the temperature difference between the head and tail of the strip, makes the strip performance uniform and stable, and improves the precision and yield rate of cold-rolled strip.
Strong cold plastic deformation technology: Strong deformation equipment and process, realize large-reduction cold deformation, combined with rapid annealing, realize fine-grained alloy structure, improve mechanical properties and comprehensive yield rate.
Advanced short-process processing technology for copper materials
Short-process processing technology refers to a production method in which liquid metal is directly solidified, rolled, drawn, or deformed. The overall yield rate is about 30% higher than that of traditional processes, and the energy consumption is about 70% of that of traditional processes.
Material design based on application scenarios
Microchannel heat exchanger is a heat exchanger with a channel equivalent diameter of 10-1000μm. Compared with conventional heat exchangers, microchannel heat exchangers are not only small in size but also have a large heat transfer coefficient and high heat transfer efficiency. Energy-saving and environmental protection effects of copper-based microchannel heat exchanger technology:
Environmental advantages: Refrigerant consumption is reduced by 70%;
Energy-saving advantage: heat exchange efficiency increased by more than 30%;
Cost advantage: weight reduction of more than 30%, cost reduction of 30%;
Compared with the finned copper tube heat exchanger system, the cooling capacity is increased by 3.4%, the power is reduced by 1.4%, and the energy efficiency ratio is increased by 0.16; the refrigerant charge can be reduced by 20% to 35%.
Copper matrix composites
Copper/graphene composites
Graphene is the material with the highest known carrier mobility. Its room temperature mobility is greater than 150,000 cm2/(V·S), 100 times that of silicon. Its theoretical conductivity is 10×10⁷S/m, which is higher than copper (5.7×10⁷) and silver (6.3×10⁷).
If the existing copper materials are replaced with copper/graphene composite materials, the copper consumption of a 20KW motor can be reduced by 12.33%. If all motors in China are replaced with super copper motors, about 18.5 billion kWh of electricity can be saved each year.
Copper/graphene composite materials belong to the deep processing industry of copper and are still in the pilot stage. There is no market development for the time being, but there are also small-scale sales.
Dispersion Strengthened Copper
It describes the performance characteristics and process flow of dispersion-strengthened copper products.
Bimetallic composite strip preparation method
It explains the rolling composite method, copper-steel composite strip process route, cold rolling composite process, etc.
**2024SMM 19th Copper Industry Conference and Copper Industry Expo Special Report**