The production capacity and output of China's aluminum processing industry have developed into rapidly growing fields, including civilian ordinary aluminum and aluminum alloy plate, strip, foil, aluminum profiles for construction and rail transit, canning materials, and aluminum plate substrates for printing. The incremental part is mainly composed of private enterprises. China is a major country in the aluminum processing industry.
In recent years, the material development of aluminum and aluminum alloys has mainly focused on two directions: (1) developing new high-strength and high toughness aluminum alloy materials to meet the needs of special fields such as aerospace, transportation, and military facilities; (2) Develop civil aluminum alloys with different properties and functions to meet new materials for different conditions and applications. The widespread application of aluminum alloys has promoted the development of aluminum alloy processing and preparation technology, but with the continuous improvement of performance requirements for aluminum alloy products, new requirements have also been put forward for aluminum alloy processing technology. Valuing and strengthening the research on the basic characteristics of aluminum alloys and the construction of systematic theories, further improving the understanding of the processing characteristics of aluminum alloys, is the only way to achieve technological innovation in aluminum alloy processing.
1. Research on the basic characteristics of aluminum alloy materials
A systematic and in-depth study of the fundamental characteristics of aluminum alloys is the foundation for innovation in aluminum alloy processing technology. On the basis of the existing aluminum alloy processing theory, excellent instruments and equipment such as computers and high-speed high-definition cameras are used to study the heat and mass transfer behavior of aluminum alloy melt solidification process, the evolution law of aluminum alloy solid deformation and precipitation phase during heat treatment process, and the constitutive relationship between multiphase microstructure interface comprehensive performance. A self owned and systematic theoretical system of aluminum alloy processing technology is formed. At the same time, combining current aluminum alloy processing equipment and production preparation technology to guide and optimize the current aluminum alloy production and processing technology, in order to achieve innovation in aluminum processing technology and materials.
(1) Research on the basic characteristics of aluminum alloy melting and casting. Study the distribution of thermal field during the solidification process of different types of aluminum melts under different cooling rates and the initial shape of the solidification front of the melt, explore the evolution law of its shape during the advancement of the solidification front, and the influence law on the internal thermal stress field of the billet; Study the redistribution of solutes during the solidification process, understand the types, thermodynamic and kinetic mechanisms of formation and growth of primary solidification precipitates, as well as the distribution patterns of different types of primary solidification precipitates and the formation mechanisms of various defects during the solidification process.
(2) Research on the basic characteristics of plastic deformation of aluminum alloy. Study the influence mechanism of external deformation force on the fragmentation of primary solidification precipitates of different sizes/types; Study the intrinsic relationship between external deformation force deformation velocity deformation variable deformation temperature distribution deformation resistance material cracking limit residual internal stress; Study the types of deformation precipitates, the thermodynamic and kinetic mechanisms of their formation and growth.
(3) Research on the basic characteristics of aluminum alloy heat treatment. Study the thermodynamic and kinetic mechanisms of the dissolution of different types of primary solidification precipitates/deformation precipitates during the solid solution heat treatment of aluminum alloys; Study the heat transfer mechanism and residual internal stress variation law of aluminum alloy during rapid quenching treatment; During the aging heat treatment process, explore the thermodynamic and kinetic mechanisms of the formation and growth of different types of precipitation phases, and grasp the distribution patterns of different types of precipitation phases; Study the interaction mechanism between different types/sizes of precipitate phases and interfaces with point/line defects, the influence of particle spacing and grain boundaries of different types/sizes of precipitate phases on the motion of line defects, and the initiation and propagation of cracks; Conduct in-depth research on the influence of precipitation phase types/sizes/distributions on the static/dynamic mechanical properties and corrosion resistance of materials, as well as the corresponding relationship between the static/dynamic mechanical properties of materials and their resistance to high-speed impact damage.
2. Research and Proposal on Civil Aluminum Alloy Materials
Aluminum alloy materials have been widely used in the fields of civil aviation, transportation, 3C electronics, new energy, sports, and construction. The fierce market competition has promoted the improvement of quality and performance requirements for civilian aluminum alloy products. Therefore, only by further exploring the potential of aluminum alloys, researching and developing excellent civilian aluminum alloy materials and processing technologies, can we better meet market demand.
2.1. High performance aluminum alloy for civil aviation
(1) Engineering preparation technology for new high-performance rare earth aluminum alloy materials for civil aviation. Conduct in-depth basic research on the application of rare earth elements in high-performance rare earth aluminum alloys for civil aviation, reveal the influence mechanism of rare earth elements in aluminum alloys, systematically study the microstructure evolution law under thermal mechanical conditions, and the relationship with performance, and form a basic theoretical system for the composition design, preparation and processing of high-performance rare earth aluminum alloys; Further research will be conducted on the engineering preparation and application of new high-performance rare earth aluminum alloy materials, forming a complete set of production processes and application technologies for new high-performance rare earth aluminum alloy deformation materials, with stable batch production capacity, achieving installation and application on civil aviation aircraft, and meeting the batch production needs of civil aviation aircraft.
(2) New high-strength, corrosion-resistant, heat-resistant aluminum alloy. Breakthrough key technologies such as composition design and correct control technology for high-strength and heat-resistant aluminum alloys, casting and forming control technology for high alloy content heat-resistant alloys, multi-stage homogenization treatment technology, and high-temperature stability thermal strength phase structure and performance control technology for rare earth Sc, Er, etc., to form a quality stability control preparation technology for high alloying ingots, and develop new materials for high-strength and heat-resistant aluminum alloys containing rare earth elements; Carry out engineering research on high-strength and heat-resistant aluminum alloy materials to provide technical reserves for typical components applied in the civil aviation field.
(3) High strength, tough, corrosion-resistant, damage tolerant aluminum alloy. In response to the design requirements for durability damage tolerance and corrosion resistance of civil aviation aircraft, the development of 700 MPa strength grade high corrosion resistance and high toughness aluminum alloy sheets is an inevitable trend. Through research on new alloy composition design and optimization, multi-level homogenization treatment of dispersed phase particles, deformation microstructure control during rolling process, and plate shape control, we plan to develop 700 MPa strength grade high corrosion resistance and high toughness aluminum alloy pre stretched medium thick plates with excellent strength fracture toughness corrosion resistance matching, providing technical reserves for key structural components in civil aviation applications.
(4) In situ self generated nanoparticles enhance high-performance aluminum based composites. This material has the advantages of high specific strength, specific modulus, good fatigue resistance, good heat resistance, corrosion resistance, and relatively low preparation cost. It is currently a breakthrough aluminum alloy new material. Master the control techniques for the morphology and size of in-situ self generated nanoparticles, and use high-frequency pulse magnetic field and high-energy ultrasonic field control techniques to control the aggregation and distribution of nanoparticles, optimize the in-situ self generated nanoparticle reinforced high-performance aluminum based composite DC casting technology. While improving the alloy structure, achieving uniform distribution of nanoparticles within the alloy grains and grain boundaries significantly enhances the strength, plasticity, and fatigue resistance of aluminum alloy materials, enabling large-scale production and market application of industrial ingots and aluminum products.
(5) Key technologies and application research for high-quality preparation and processing of aviation aluminum alloys. For high-quality aluminum alloy materials used in aviation, in-depth research is conducted on the intrinsic relationship between alloy composition, microstructure, properties, preparation and processing, as well as the strengthening and toughening mechanisms and other scientific issues, as well as detailed control technologies. Organizational control principles and safety service guidelines are established, and a basic data platform is constructed to break through the key technical bottlenecks of high reliability, high stability, and high homogeneity preparation of large aluminum alloy structural materials. This provides theoretical basis and key technical support for the complete independent and controllable production of aviation aluminum alloy structural materials.
2.2. Lightweight aluminum alloy for transportation
(1) Research and development of automotive grade deformed aluminum materials that balance lightweight and safety, and high-quality industrial production. China is the world's largest automobile consumer market, and the design and manufacturing of traditional fuel vehicles and new energy vehicles will further increase the application of aluminum materials, including all aluminum body and battery cases for new energy vehicles. There is an urgent need for the design, research and development, and high-quality industrialization of deformed aluminum alloy materials. Taking enterprises as the main body, through the close integration of "research, production, and application", joint research and development are carried out to address the problem links in the entire process, refine and quantify the system details and standardized parameters in the production and preparation process, establish a traceable production management system and system, and achieve high-quality and stable production and application of typical deformed aluminum materials for vehicles.
(2) Basic research on the application of the correlation between aluminum design and "process structure performance". Based on the application performance requirements of 6 XXXXX series aluminum materials (plates and profiles) for automobile body structure and 3 XXXXX series aluminum materials for battery shell, and relying on quantitative characterization techniques of multidimensional and multi-scale microstructure, alloy design and process research based on comprehensive performance requirements, alloy design and process research based on single excellent performance, and application performance (forming, connection, etc.) research and evaluation are carried out. Aluminum alloy materials for automobile body and its structure, battery shell are developed, and low-cost and high stability production and preparation are achieved.
(3) High formability and high-strength aluminum alloy. By optimizing the chemical composition and processing technology of aluminum alloy, a high-strength aluminum alloy material with equivalent deep drawing performance (T4P state) to the current automotive aluminum 6016 alloy and equivalent strength to 2024-T351 state after short-term baking has been developed, which meets the performance requirements of impact resistant dent covers for automotive lightweighting.
(4) Large size high-strength foam aluminum alloy. Foam aluminum has the characteristics of both porous structure and metal, and has many excellent properties such as light weight, high specific strength, energy absorption, shock absorption, damping, sound absorption, heat dissipation, electromagnetic shielding, etc. The simulation technology is used to deeply and systematically study the interaction between foam aluminum structure and material properties, optimize the process parameters of industrial production, simplify the production process, reduce production costs, and realize the market application of high-strength and large specification foam aluminum alloy materials in the field of transportation lightweight.
2.3 3C electronic aluminum and other aluminum alloys
(1) Development and industrialization of rare earth aluminum alloys. China has abundant rare earth resources, and the aluminum alloy industry has a large scale. Previous studies have shown that the combination of some rare earth elements (RE) with aluminum alloys can effectively improve their performance. However, China has not yet developed stable rare earth aluminum alloys for application, nor has it developed rare earth aluminum alloys with Chinese characteristics internationally. Therefore, it is necessary to continue to increase efforts in related research and industrialization processes. By closely combining research, learning, and application, further research on the basic application of rare earth elements in aluminum alloys is carried out, and the influence mechanism of rare earth elements in aluminum alloys is deeply understood. Several rare earth aluminum alloys with practical value are developed and promoted for application.
(2) 5G high surface, high strength, and high thermal conductivity aluminum alloy. By optimizing the chemical composition of the alloy and regulating the material structure reasonably, studying the effects of alloy composition, deformation processing, and heat treatment processes on the strength, thermal conductivity, and anodizing performance of the alloy, the control of alloy grains and second phase compounds can be achieved; Through organizational regulation and research on anodizing and electrolytic coloring processes, an anodized film with uniform coating, no color difference, and no defects such as black spots and black lines has been obtained. High surface, high thermal conductivity, and high strength aluminum alloy materials have been developed to meet market demand for 5G mobile phone cases, mobile phone middle plates, extruded aluminum materials, and rolled sheets.
(3) Efficient and low-cost aluminum alloy anode for aluminum air batteries. Thoroughly and systematically study the unique alloying elements of aluminum alloy anodes, such as low melting point metal elements, deformation processing, and heat treatment processes, and their effects on the electrochemical activity and self corrosion resistance of aluminum anodes. Conduct basic research on the activation and passivation characteristics of aluminum alloy anode materials, develop aluminum alloy anode materials that meet the requirements of aluminum air batteries, and realize the market-oriented application of aluminum air batteries in automotive lightweighting, emergency power supply, and other fields.
(4) 800 MPa strength aluminum alloy. Breaking through the existing design range of high-strength aluminum alloy components, we have developed a new type of aluminum alloy material with a strength of 800 MPa in the 7XX series. We will focus on conducting research on key technologies such as industrial composition design and correct control of 800 MPa grade high-strength aluminum alloy, forming of high alloy ingots and preparation of high metallurgical quality ingots, regulating the uniformity of microstructure during hot processing, and controlling precision heat treatment processes. We will develop quality stability control technologies for batch production of high alloy ingots and establish detailed control technologies for the evolution and structure of microstructure during processing and heat treatment; Complete the development of typical components and verify their application under simulated service conditions, preliminarily achieve the lightweight replacement of high-strength structural materials for ships, and provide technical reserves for the lightweight design and preparation of typical structural components for applications in aerospace, aviation, transportation, and other fields.
(5) High strength, tough, corrosion-resistant, heat-resistant aluminum alloy drill rods for petroleum exploration. Compared with steel drill pipes, aluminum alloy drill pipes have the advantages of low specific density, high strength, low bending stress, and resistance to acidic gases such as H2S and CO2 corrosion. They also have greater drilling depth capability and stronger shock absorption ability. Therefore, aluminum alloy drill pipes have obvious advantages in the exploration and development of deep wells, ultra deep wells, and acidic gas wells. Research and optimize the heat treatment process of alloys in high solute states to control the microstructure, in order to achieve a better combination of MPt, GBP, and PFZ, and to optimize the matching of high strength, high toughness, corrosion resistance, and heat resistance of alloys; Study the deformation behavior of alloys and establish an alloy microstructure evolution model; Understand the relationship between factors such as composition, microstructure, and macroscopic properties, establish models for time hardening, stress corrosion, and fracture toughness, achieve correct control of microstructure, and develop and produce high-strength, tough, corrosion-resistant, heat-resistant aluminum alloy drill rods for petroleum exploration that meet market demand.
(6) Development and industrialization of green processing technology for aluminum alloy materials. In the face of resource and energy shortages, the comprehensive utilization of resources and technological innovation are particularly important. The system conducts basic research on the application of recycled aluminum alloys, deeply understands the coupling effects of multiple elements in aluminum alloys and their impact mechanisms on material structure and properties, establishes an aluminum alloy recycling and reuse system, develops low-energy, low-cost, high-performance green preparation and processing technologies for aluminum alloy materials, and provides theoretical and technical support for the preparation of low-cost green and environmentally friendly aluminum alloys and "one aluminum multi energy" with application value, achieving China's strict energy-saving and emission reduction goals year by year and the green upgrading of the aluminum industry.
3. Conclusion and outlook
High performance, high quality, high uniformity, low cost, and low-carbon environmental protection are still the main directions for the development of new materials for civil aluminum alloys and aluminum processing technology. One is to develop excellent casting technology, continuously improve energy utilization efficiency, reduce emissions, and enhance the control level of metallurgical quality, chemical composition, and microstructure of ingots; The second is to integrate and apply contemporary excellent technological achievements, develop high-precision automation, specialization, and large-scale technical equipment, improve efficiency, and ensure the large-scale production of high-quality and highly uniform products; The third is to fully utilize the application of computer simulation technology in the fields of new material research and development, processing, processing technology, and mold design and optimization, significantly shorten the development cycle, reduce development risks, improve production efficiency, and reduce costs.
At present, aluminum alloy processing materials are developing towards multi alloy, large width, high strength and toughness, high purity, high precision, high stability, superplasticity and superconductivity. This inevitably requires a lot of detailed work in technological innovation research, from material mechanism research to process element control, processing influencing factors, reasonable process line parameter formulation, strict quality tracking and supervision, etc., to establish aluminum alloy basic characteristic characterization, processing technology database and product quality inspection and evaluation system, and achieve innovative development of excellent civil aluminum alloy material processing technology.
