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What Are Aluminum Alloys?
Aluminum alloys are a combination of aluminum elements and several other alloying elements. Aluminum alloys generally contain aluminum and other alloying elements such as manganese, chromium, tin, silicon, copper, and magnesium. These elements are not combined in the above-listed order, nor is it compulsory to include all the elements in the blend.
Aluminum alloys are often more cost-effective than pure aluminum and have a lower melting point. Consequently, these aluminum alloys consume low heat energy while processing. However, the applications determine the alloying elements to combine and the proper measures to create aluminum alloys.
Manufacturers combine aluminum with these metallic elements to achieve new CNC machining materials with enhanced mechanical properties, strength, workability, good corrosion resistance, durability, etc. These elements are mixed with aluminum while molten to create a homogenous material after cooling. In addition, the aluminum association categorized aluminum alloys as cast and wrought alloys.
6061 Alloy Chemical Composition
The 6061 aluminum alloy primary alloying elements comprise 97% aluminum, 0.2% chromium, 0.28% copper, 0.6% silicon, 1.0% magnesium, and a small number of other elements. There is an extensive list of aluminum alloys, each with a unique code number, i.e., 1000 series, 6000 series, and 7000 series. Each of these digits indicates specific properties that describe the aluminum alloys’ uniqueness.
For instance, the 6061 aluminum is a popular member of the 6000 series. Its initial number, 6, represents the major alloying elements (magnesium and silicon). This alloy contains these elements in higher portions than other alloying elements.
Meanwhile, the second digit indicates impurity control demanding adequate attention as the alloying elements are mixed with the base aluminum element. As a result, the number “0” in 6061 shows that no particular care is required to tighten controls. The third and fourth digits have no specific function than indicating the alloys present with their series.
However, it is a different case with the 1000 series. Its last two digits indicate the minimum additional purity beyond 99%. For instance, the 1000 and 1050 series show that the alloy would possess 99% and 99.5% minimum aluminum, respectively.
Characteristics of 6061 Aluminum
The 6061 aluminum alloy is the most widely used aluminum grade across industries, whether in its angle, bar, sheet, or plate form. The 6061 aluminum’s medium to high strength, good weldability, and machinability makes it a versatile alloy.
Usually, the heat-treated 6061 aluminum alloy has improved strength and resistance to corrosion. This treatment involves exposing the alloy to a high temperature below the melting point. Consequently, tampering strengthens the aluminum by lowering its internal stresses and brittleness.
Material Properties of 6061 Aluminum
The material properties of 6061 aluminum include but are not restricted to thermal, processing, and physical properties. The table below illustrates some of the material properties of 6061 aluminum alloy:
| Material Properties | Value |
| Hardness, Rockwell A | 40 |
| Hardness, Rockwell B | 60 |
| Hardness, Vickers | 107 |
| Hardness, Brinell | 95 |
| Hardness, Knop | 120 |
| Modulus of Elasticity | 68.9 Gpa or 10,000 ksi |
| Fatigue Stress | 14,000 psi or 96.5 Mpa |
| Yield Stress | 35,000 psi or 241 Mpa |
| Tensile Stress | 42,000 psi or 290 Mpa |
| Ultimate Bearing Stress | 88, 000 psi or 607 Mpa |
| Shear Stress | 30,000 psi or 207 Mpa |
| Elongation at Break | 12% |
| Poisson’s Ratio | 0.33 |
| Machinability | 50% |
| Shear Modulus | 3770 ksi or 26 Gpa |
| Thermal Conductivity | 167 W/m-k |
| Specific Heat Capacity | 0.896 J/g-ºC |
Common Trade Names for 6061 Aluminum Alloy
The typical trade names of the 6061 aluminum alloy include
- 6061-T651
- 6061-O
- 6061–T6
- 6061-Ta4
- Alloy 61s
Applications of 6061 Aluminum Alloy
The 6061 aluminum alloy has diverse uses in several industries due to its remarkable strength, lightweight, resistance to rust, and affordability. Asides from making bicycle frames, aluminum cans, electrical fittings, industrial parts, and food containers, here are other applications of 6061 alloy:
Automotive Parts
The 6061 aluminum alloy is used in the automotive sector to make various parts. This alloy has excellent strength for making frame components such as engine, vehicle, brake, suspension, and drivetrain components.
Likewise, its lightweight attributes render it an ideal material for body panels. It helps to reduce the vehicle’s overall weight without compromising its durability and strength.
Aircraft Components
Aluminum 6061 is one of the most used materials in aerospace applications because of its excellent strength-to-weight ratio and high corrosion resistance. Manufacturers often use the 6061 alloys to create aircraft components such as bulkheads, fuselages, stabilizers, wings, and other structural components for commercial or military aircraft. The flexibility and durability of this alloy make it the perfect choice for applications with high demand.
Sporting Goods
The sporting sector benefits from the outstanding corrosion resistance attributes and the strength-to-weight ratio of the aluminum 6061. Manufacturers and product designers often use this alloy to produce sporting goods like skateboard decks, baseball bats, hockey stick holds, golf club shafts, surfboards, and tennis racquet handles. The flexibility of the alloy 6061 renders it a suitable material for this application.
6061 Aluminum Alloy Operating Temperature Range
The operating temperature range of a particular alloy describes its hot working, aging, and annealing temperature range. The ideal hot working temperature for aluminum 6061 falls within the range of 260-372 ºC.
Also, you can anneal the 6061 aluminum at 413 ºC for about 2-3 hours. Then, you can cool the metal at a controlled temperature of 10 ºC per hour until it reaches 260 ºC. Additionally, 6061 aluminum aging is best done at 160 ºC for precisely 8 hours before cooling in the air.
Is 6061 Aluminum Weldable?
The 6061 aluminum is highly weldable. You can weld it routinely using the appropriate filler material. This filler material helps to prevent all welding complexities involved in 6061 aluminum-solidification cracking. To get the best result from welding 6061 aluminum, you must utilize the perfect filler material, which includes 5356 or 4043 aluminum alloy.
More importantly, it is advisable never to use 6061 filler material to weld 6061 aluminum alloy to prevent cracking.
Is 6061 Aluminum Strong Enough?
The tempered grade of the 6061 aluminum used determines the material’s strength. For example, the strength of the 6061-T6 depends on the yield and ultimate tensile strength. The yield strength is measured by the permissible stress limit for an alloy when force is applied. A material gets permanently deformed by an exerted force above the maximum yield strength. Such a material will be unable to maintain its original shape or structure.
Moreover, a material’s tensile stress refers to the highest stress beyond which it fails and breaks. The ultimate tensile stress of T6 Temper 6061 aluminum is at least 42,000 psi (290 Mpa), while its yield stress is about 35,000 psi (241 Mpa).
Helpful Tips to Consider When Selecting an Aluminum Grade?
The following are helpful tips to consider when choosing an aluminum grade for your projects:
- Strength
- Corrosion resistance
- Workability
- Weldability
- Machinability
- Heat treatment
- End-use application
Aluminum alloys are of various grades and shapes, and the end-use application often determines the aluminum grade to use. Determining each grade’s attributes is more accessible when the end-use is well-defined. However, you can choose the grade that aligns with the required properties.
For instance, if your project requires a material with high weldability properties without too much strength emphasis, 1100 aluminum alloy is the ideal option. It has excellent weldability but doesn’t fit high-strength applications so well.
Conclusion
The article has provided detailed information on the 6061 aluminum alloy. Now that you understand this aluminum alloy’s composition, properties, and applications, you should be able to decide if it suits your products.
However, AT-Machining is your option if you need professional assistance with your next manufacturing project. We offer an extensive range of manufacturing capabilities that fetches the best results. Our engineers and expert technicians are always ready to attend to all your prototyping and production needs. Don’t hesitate to contact us today, and let’s discuss the details of your next project.
