Metallurgy plays a crucial role in aviation development. With the discovery of new materials, new applications have been found to be applied to these or to rapidly improve existing designs. Aluminum appears to be the king of aircraft manufacturing, although some new alloys have been used in recent years. These superalloys remain quite expensive for aircraft builders. Aluminum alloys have good weight and cost advantages and remain widely used in the industry.
Aluminum Alloy Heat Treatment:
Aluminum alloys are identified by a four-digit system. The first digit gives the alloy group, while other alloy combinations contain the alloys present. Below we have compiled a list of the most commonly used aircraft aluminum alloys and their respective properties. Heat treatment, with the use of copper (Cu) and zinc (Zi) in aluminum alloys, alters their properties, allowing the alloy to harden and soften by heating. The resulting temper designation is indicated by the alphanumeric combination following the alloy number. The most commonly found temper indices are T3 and T6. T3 is achieved through solution heat treatment and cold working after flattening. T6 is achieved through solvothermal treatment and artificial aging.
Aluminum Alloy Element Composition:
Each alloy has its own properties based on its elemental composition. For example, 2024 alloy has 4.5% copper, 0.6% manganese, and 1.5% magnesium. 6061 has 0.25% copper, 0.6% silicon, 1.0% magnesium, and 0.25% chromium. 5052 has 2.5% magnesium and 0.25% chromium. 3003 alloy only adds 1.2% manganese.
Aluminum Alloy Types and Mechanical Properties:
The mechanical properties of an alloy are an important factor in determining its use during construction. The following list provides some typical properties:
2024-T3 Aluminum Alloy:
This is the most common high-strength aluminum alloy. It is of high quality for aircraft applications. 2024-T3 aluminum sheets are considered aircraft alloys due to their strength and also have excellent fatigue resistance. It is generally not recommended for use in applications involving aircraft. Typical applications for 2024-T3 Alclad aluminum sheet include fuselage and wing shells, vehicle roofs, aircraft structures, and repair and restoration due to its glossy finish (2024-T3 Alclad). Its ultimate tensile strength is 62,000 PSI, and its shear strength is 40,000 PSI.
6061-T6 Aluminum Alloy:
This alloy exhibits excellent corrosion resistance and finishing properties, with no issues at the joints. The strength level of 6061-T6 aluminum sheet is approximately that of low-carbon steel. 6061-T6 aluminum sheet can be manufactured using most common techniques. Typical applications include aircraft landing pads, truck bodies and frames, structural components, etc. Its ultimate tensile strength is 45,000 PSI, and its shear strength is 30,000 PSI.
5052 Aluminum Alloy:
This non-heatable alloy series has the highest strength. It is not structural. 5052 aluminum sheet has higher fatigue strength than most alloys. 5052 aluminum sheet has excellent corrosion resistance, especially in marine applications, and excellent machinability. 5052 aluminum sheet is commonly used in the construction of fuel tanks.
3003-H14 Aluminum Alloy:
The most widely used aluminum alloy, pure aluminum is approximately 20% stronger than the 100 series compared to manganese. 3003-H14 aluminum sheet has good machinability and can be deep drawn, spun, welded, or brazed. 3003 aluminum sheet is not heat-treatable. This aluminum sheet is widely used for fairings and baffle electroplating. Ultimate strength is 21000 PSI, and shear strength is 14000 PSI.
7075 Aluminum Alloy:
Aircraft manufacturers use high-strength alloys (primarily alloy 7075) to reinforce aluminum aircraft structures. Aluminum alloy 7075 contains copper (1.6%), magnesium (2.5%), and zinc (5.6%) for ultimate strength, but the copper content makes it very difficult to weld. On the other hand, it anodizes very beautifully. 7075 boasts superior machinability, achieving excellent results. Its ultimate tensile strength is 33,000 PSI (-0) and 82,000 PSI (-T6), and its shear strength is 22,000 PSI (-0) and 49,000 PSI (-T6).
Applications in the Aluminum Alloy Machining Industry:
Current developments indicate that an increasing number of manufacturers (Boeing, Airbus) are using carbon fiber and other non-metallic materials in aircraft structures because these materials can be formed into virtually any shape and curvature. Over time, these materials will have to prove themselves as reliable as aluminum in terms of resistance to UV damage. Aluminum alloy machining is a core component of manufacturing, with applications permeating almost all high-end and modern industrial sectors. In the electronics and communications field, aluminum alloys are primarily machined into mobile phone frames/casings, laptop shells, tablet back panels, 5G base station heat sinks, and hard drive bases. Due to their heat resistance and corrosion resistance, aluminum alloys are widely used in solar panel frames, brackets, and some structural components and heat dissipation parts of wind turbine generators.
Future Development of Aluminum Alloy Machining Parts:
The aluminum alloy machining industry is the cornerstone of modern high-end manufacturing. Its future development will closely revolve around the directions of “lighter, stronger, more complex, more intelligent, and greener.” The value focus of the future aluminum alloy CNC machining industry will irreversibly shift from “equipment and labor” to “data, software, and knowledge.” The future development of the entire aluminum alloy CNC machining industry will inevitably be driven by innovators who deeply integrate materials science, digital technology, and advanced manufacturing processes, and can quickly respond to the demands of green energy and high-end equipment. Kzron, as a professional metal processing factory, undertakes various customized needs, with no minimum order quantity requirement, and accepts samples and mass production.
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