Aluminum alloy overview and applications.
Aluminum alloy is a general term for aluminum-based alloys. Major alloying elements include copper, silicon, magnesium, zinc, and manganese, while minor alloying elements can include nickel, iron, titanium, chromium, lithium, among others.
Aluminum alloy is the most widely used category of non-ferrous metal structural materials in industrial applications. It has been widely applied in various fields such as aviation, aerospace, automotive, machinery manufacturing, shipbuilding and chemical industry.
Aluminum alloy has low density but relatively high strength, approaching or exceeding that of high-quality steel. It has good plasticity and can be processed into various profiles.
Furthermore, it has excellent electrical conductivity, thermal conductivity and corrosion resistance. As a result, aluminum alloy is widely used in industry and is second only to steel in use.
Aluminum alloy is very common in our daily lives. Our doors, windows, beds, kitchen utensils, cutlery, bicycles, cars and much more contain aluminum alloy.
Ultra-high strength aluminum alloy.
Introduction: High-strength aluminum alloy has the characteristics of light weight, high strength, good processing performance and excellent welding performance. It is widely used in areas such as the aeronautical industry and the civil industry, especially in the aeronautical industry where it occupies a very important position as one of the main structural materials.
In recent decades, domestic and foreign scholars have conducted extensive research on the heat treatment process and performance of high-strength aluminum alloys, made significant progress, and greatly promoted the widespread application of such materials in various aspects of aviation industry production.
Ultra-high-strength aluminum alloy is mainly composed of AI-Cu-Mg and A1-Zn-Mg-Cu alloys. The former has a slightly lower static resistance than the latter, but has a higher usage temperature. AI-Cu-Mg series alloy is the first heat-treated reinforcing alloy developed. The development of the aeronautical industry promoted the improvement of this series of alloys.
Leagues 2014 and 2024 were developed in the 1920s and 1930s respectively, followed by the development of league 2618. The development of this series of leagues is more mature, and more than ten classes have been formulated. These alloys have been widely used as aviation materials and other materials.
The application of high strength aluminum alloy in conductors
In the international community, high-strength aluminum alloy conductors of the aluminum-magnesium-silicon type have been used for more than 70 years. Due to its advantages and continuous improvement in production technology, it has become more practical. In Europe, represented by France, it is widely used in transmission lines, representing the vast majority of the total length of the lines.
More than 50% of transmission lines in Japan use aluminum alloy. The United States and Canada also have a large proportion. Even developing countries in Southeast Asia such as India, Indonesia and the Philippines also use aluminum alloys for conductor transmission lines.
Development trend of ultra-high-strength aluminum alloy
Ultra-high-strength aluminum alloy is an important lightweight and high-strength structural material with broad application prospects. Currently, the following aspects need to be worked on:
1. Composite microalloying is an important direction for the hardening of aluminum alloys, and research and development must be carried out in-depth and systematically;
2. Improve traditional ingot metallurgy preparation technology and develop advanced spray forming preparation processes to obtain high-quality ingot structure and so on.
Ultra-high-strength aluminum alloy is developing towards high specific strength, high specific modulus, high damage tolerance and corrosion resistance. Purification smelting and advanced billet production technology are prerequisites for development, and hardening theory is the foundation.
Based on the existing reinforcement theory, firstly, combining the micromechanics theory with the microcrystal defect theory to improve the design level of alloy composition optimization;
Second, develop a comprehensive multi-level and multi-phase toughness theory, using microalloys to explore the potential of alloys, improve alloy performance, and develop new types of aluminum alloys;
Third, accurately control the microstructure of alloys to form an accurate control theory of structure and performance, and develop ultra-high-strength aluminum alloys with better comprehensive performance.
The development trend of high-strength aluminum alloy.
High-strength aluminum alloy is an important lightweight and high-strength structural material with broad application prospects. The application of aluminum and aluminum alloys is challenged by titanium and titanium alloys and composite materials, but its position as the main structural material remains basically unchanged.
Currently, the development trend of high-strength aluminum alloys is in the following aspects:
(1) Composite microalloys, adding transition elements and rare earth elements, to develop various new high-strength aluminum alloys that meet different needs.
(2) Improve the traditional ingot metallurgy preparation technology by using and researching various advanced casting purification and modification methods to improve the metallurgical quality of ingots.
(3) In-depth study of the heat treatment process of alloys in high solute state, studying the strengthening mechanism of alloy solid solution treatment precipitation and multilevel and multiphase aging precipitation under different conditions, improving the supersaturated solubility of the alloy matrix alloy, increasing the volume fraction of precipitated phases and optimizing the combination of MPt, GBP and PEZ to obtain high strength, high toughness and good corrosion resistance of the alloy.
Heat resistant aluminum alloys
Application and existing problems of rapidly solidified heat-resistant aluminum alloys
The ultimate goal of developing rapidly solidifying heat-resistant aluminum alloys is to replace titanium alloys in aircraft parts. In recent years, research results have shown that significant progress has been made in this area, and some properties of rapidly solidified heat-resistant aluminum alloys are already comparable to or even better than certain titanium alloys.
Rapidly solidified heat-resistant aluminum alloys have been used successfully to manufacture compressor blades and vanes, turbines, heat sinks, and other components in gas turbine engines. They can also be used to produce certain parts for rockets and spacecraft.
When rapidly solidified heat-resistant aluminum alloys are used to manufacture aircraft components, the cost is generally only 30% to 50% of the cost of titanium alloys, while the weight of the aircraft can be reduced by about 15%. If its heat resistance is improved, the range of applications will be expanded.
Research directions for heat-resistant aluminum alloys in the future
Future research directions for fast-solidifying heat-resistant aluminum alloys will mainly focus on the following aspects:
Development of new fast and low-cost solidification processes. Compared with the RS/PM process, the spray deposition rapid solidification process simplifies the production process, avoids the interface oxidation problem of the original powder particles, and can improve the toughness of the alloy while reducing production costs.
Therefore, the rapid solidification process of spray deposition should be improved for practical application.
Further research into the heat resistance mechanism of the alloy, including the role of the supersaturated matrix during the heating process.
Study the causes of thermal embrittlement in the alloy and find solutions to further improve its toughness.
Aluminum-based composite materials.
Composite materials are materials with strong vitality that emerged to meet the needs of modern scientific development. They are composed of two or more materials with different properties, combined by different technological means.
Composite materials can be divided into three categories: polymer-based composites (PMCs), metal-based composites (MMCs) and ceramic-based composites (CMCs).
The matrix of metal-based composites is mainly aluminum, nickel, magnesium, titanium, etc. Aluminum has many characteristics in the manufacture of composite materials, such as light weight, small density, good plasticity, easy to master composite technology and easy processing.
In addition, aluminum-based composites have high specific strength and specific stiffness, good high temperature performance, better fatigue and wear resistance, excellent damping performance, and low thermal expansion coefficient.
Like other composite materials, it can combine specific mechanical and physical properties to meet the needs of products. Therefore, aluminum-based composites have become one of the most widely used and important materials among metal-based composites.
Main types and application overview.
According to different types of reinforcement, aluminum-based composites can be divided into fiber-reinforced aluminum-based composites and particle-reinforced aluminum-based composites.
Fiber-reinforced aluminum-based composites have a series of excellent properties such as high specific strength, high specific modulus, good dimensional stability, etc., but they are expensive.
Currently, they are mainly used in the aerospace field as structural materials for spacecraft, artificial satellites, space stations, etc. Particle-reinforced aluminum-based composites can be used to manufacture structural materials for satellites and aerospace, aircraft components, metallic mirror optical systems, automotive components;
Furthermore, they can also be used to manufacture microwave circuit components, precision parts for inertial navigation systems, turbocharger thrusters, electronic packaging devices, etc.
The basic components of aluminum-based composites are:
Aluminum and its alloys are suitable as matrices for metal matrix composites. The reinforcement of aluminum-based composites can be made of continuous fibers, short fibers or particles that vary from spherical to irregular shapes.
At present, particle reinforcement materials for aluminum-based composites include SiC, AL2O3, BN and so on. Intermetallic compounds such as Ni-Al, Fe-Al and Ti-Al have also been used as reinforcing particles.
Performance of Aluminum-Based Composite Materials.
1. Low density.
2. Good dimensional stability.
Resistance, modulus and plasticity. The addition of reinforcements in aluminum-based composite materials increases their strength and modulus, while decreasing their plasticity.
4. Wear resistance.
High wear resistance is one of the characteristics of aluminum-based composite materials (reinforced with SiC or Al2O3).
5. Fatigue and fracture toughness.
The fatigue strength of aluminum-based composite materials is generally higher than that of the base metal, while the fracture toughness decreases. The main factors that affect the fatigue and fracture performance of aluminum-based composite materials are the bonding state of the interface between the reinforcement and the matrix, the properties of the matrix and the reinforcement itself, and the distribution of the reinforcement in the matrix.
6. Thermal performance.
Thermal expansion mismatch between reinforcement and matrix is difficult to avoid in any composite material.
In order to effectively reduce the thermal expansion coefficient of composite materials and keep them thermally combined with semiconductor materials or ceramic substrates, low expansion alloys are often used as matrices and composite materials with high volume fractions of particles of different sizes are prepared.
Table 1 Performance of Common Reinforcement Materials
| Name of fiber or particle | Density | Tensile strength | elastic modulus |
| ρ (g·cm-1) | σb/GPa | E/GPa | |
| Fiberglass (high modulus) | 2.5-2.6 | 3.8-4.6 | 93-108 |
| Carbon fiber (high modulus) | 1.75-1.95 | 2.3~2.9 | 275-304 |
| boron fiber | 2.5 | 2.8-3.1 | 383-392 |
| aramid fiber | 1.43-1.46 | 5 | 134 |
| Al2O3 fiber | 3.97 | 2.1 | 167 |
| SLC Fiber | 3.18 | 3.4 | 412 |
| SLC Mustaches | 3.19 | 3-14 | 490 |
| Al2O3 particles | 3.95 | 0.76 (σtc) | 400 |
| Matrix alloy | SiCp (volume fraction) /% |
AND /GPa |
σ 0. 2 /MPa |
σb /MPa |
δ /% |
| 6061 | 0 15 20 25 30 40 |
68 96 103 113 120 144 |
275 400 413 427 434 448 |
310 455 496 517 551 586 |
12 7.5 5.5 4.5 3.0 2.0 |
| 2124 | 0 20 25 30 40 |
71 103 113 120 151 |
420 400 413 441 517 |
455 551 565 593 689 |
9 7.0 5.6 4.5 1.1 |
Applications of Aluminum-Based Composite Materials.
(1) Applications of Aluminum-Based Composite Materials in the Automotive Industry.
Research on the application of aluminum-based composite materials in the automotive industry began earlier. In the 1980s, Toyota successfully prepared engine pistons using composite materials.
In the United States, particle-reinforced aluminum-based composite materials were developed to manufacture automotive brake discs, which reduced weight, improved wear resistance, significantly reduced noise, and had rapid frictional heat dissipation.
The company has also used particle-reinforced aluminum-based composite materials to manufacture automotive components such as engine pistons and gearboxes.
The gearbox made of composite materials has significant improvements in strength and wear resistance compared with the aluminum alloy gearbox. Aluminum alloy composites can also be used to manufacture brake rotors, brake pistons, brake pads, calipers and other brake system components.
Aluminum-based composite materials can also be used to manufacture automotive parts such as drive shafts and rocker arms.
(2) Applications of aluminum-based composite materials in the aerospace industry
The development of modern science and technology has imposed increasingly higher requirements on the performance of materials, especially in the aerospace field, where it is necessary to manufacture lightweight, flexible and high-performance aircraft and satellites. Aluminum-based composite materials can meet these requirements.
By using the investment casting process to develop composite materials, the material can replace titanium alloy in manufacturing large-diameter, heavy-weight camera lens mounts for aircraft, significantly reducing their cost and weight while improving the thermal conductivity.
At the same time, this composite material can also be used to manufacture support brackets for satellite reaction wheels and directional structures.
(3) Applications in electronics and optical instruments
Aluminum-based composite materials, especially reinforced aluminum-based composite materials, are suitable for manufacturing shell materials of electronic equipment, heat sinks and other electronic components due to their advantages of low coefficient of thermal expansion, low density and good thermal conductivity.
The coefficient of thermal expansion of particle-reinforced aluminum-based composite materials can completely match that of electronic device materials, and they also have excellent electrical and thermal conductivity. In terms of research on the application of precision instruments and optical instruments, aluminum-based composite materials are used to manufacture components such as support structure and secondary mirror of telescopes.
In addition, aluminum-based composite materials can also be used to manufacture precision parts for inertial navigation systems, rotating scanning mirrors, infrared observation mirrors, laser mirrors, laser gyroscopes, reflectors, mirror bases and mounting brackets. optical instruments for many precision and optical instruments. instruments.
(4) Application in sports equipment.
Aluminum-based composites can be used to make tennis rackets, fishing rods, golf clubs, and skis as substitutes for wood and metallic materials. Bicycle chains made with particle-reinforced aluminum-based composites are lightweight, stiff and do not bend or deform easily, with better performance than aluminum alloy chains.
Aluminum-based composites reinforced with silicon carbide particles.
The most promising aluminum-based composite material is aluminum-based composites reinforced with silicon carbide particles.
Aluminum-based composites reinforced with silicon carbide particles are widely recognized as one of the most competitive types of metal matrix composite materials.
Although its mechanical properties, especially strength, are not comparable to those of continuous fiber composites, it has significant cost advantages and is easier to prepare with more flexible and diverse preparation methods. It can also be secondary processed using traditional metallurgical equipment, facilitating mass production.
In the 1990s, after the end of the Cold War, due to the reduction in investment in the defense industry by several countries, even high-tech fields such as aerospace found it increasingly difficult to accept the high cost of products. fiber-reinforced aluminum base. composites.
Therefore, particle-reinforced aluminum-based composites have once again received widespread attention. Especially in recent years, as a key load-bearing component, it has finally found its way into advanced aircraft, and its application prospects are becoming more optimistic, which has led to a resurgence of research and development work.
Development trends and directions
Currently, the main problem faced by aluminum-based composites is high manufacturing costs, especially for fiber-reinforced aluminum-based composites.
With further research into reinforcement-matrix bonding theory, as well as continued development of low-cost reinforcements and preparation processes, along with recycling of waste materials, aluminum-based composites will maintain excellent performance and at the same time they will become more economical. effective, making its fields of application increasingly broader.
The development prospects of aluminum alloys
The development directions of aluminum alloys are:
- Aluminum composite alloys for heat exchangers.
- Rare earth aluminum alloys.
Adding appropriate rare earth elements to aluminum alloys can have a refining effect, including:
Rare earths have a refining effect on aluminum alloys.
Rare earths have a modifying effect on aluminum-silicon alloys.
Rare earth aluminum alloys are an ideal material to replace copper in the manufacture of wires and cables. Aluminum ingots produced by Chinese foundries have a high silicon content due to the influence of natural resources, with silicon being the main harmful impurity that affects conductivity.
In the past, the electrical conductivity of aluminum wires produced in China often did not meet the standards of the International Electrotechnical Commission, which has become a long-standing problem for the aluminum wire industry.
Chinese scientists solved this problem with the help of rare earths. They were the first in the world to use trace amounts of rare earths to treat liquid aluminum, allowing it to form silicon compounds with silicon precipitation at grain boundaries.
Furthermore, the microbonding effect of rare earths overcomes the harmful effects of silicon, significantly improving conductivity. Rare earths can also refine grains and strengthen the matrix, improving the mechanical strength and processing performance of wire and cable.
As a result, the electrical conductivity of aluminum wires and cables made in China is not only slightly higher than the standards of the International Electrotechnical Commission, but the mechanical strength has also increased by 20%, the corrosion resistance has doubled, and the wear resistance has increased. about 10 times.
This completely changed the backwardness of Chinese aluminum wire and cable production, raising the products to the international advanced level.
Conclusion
In fact, our group found the research report on aluminum alloys organized by the college to be very significant and necessary.
Through self-study, we gained some insights that we did not have before when conducting the project report.
First, we learn the self-learning method that will accompany us in society;
second, we learn how to collect and organize information;
third, we learned what teamwork is and understood the importance of unity and cooperation. Before we didn't have much understanding of this, but through these learning activities, we now know better.
At first I didn't know what aluminum alloy was. I only knew that it was used in many places in life, but I didn't know its properties and classification. Now I know and learned about it through self-study in the project report.
