6061-T6 Aluminum vs 7075: Complete Comparison Guide

Introduction

In choosing the right type of aluminum alloys to use in precision manufacturing projects, two alloys 6061-T6 and 7075 are considered as the major choice amid a deeper dilemma confronting the engineers and manufacturers in their decision. The two alloys present different and are commonly accepted in fields of aerospace to the automotive connector molds. The knowledge of their composition differences, as well as properties, and applications, is the key to making an informed material choice that would guarantee the best performance, cost-effective decisions as well as the success in manufacturing.

With that said, this detailed comparison will examine the major properties of the two alloys; this can guide you to come up with the right aluminum grade depending on your unique project needs.

What Is 6061 Aluminum?

6061 aluminum is a precipitation hardened aluminium alloy that has magnesium and silicon as its major alloying agents. The T6 name means that the material was solution heat treated and artificially aged to provide maximum strength characteristics. This alloy with multiple uses is famous in the great balancing power of strength, corrosion resistance and ease of use.

It was originally made in the 1960s but due to its medium strength, weldability and high machinability it has become one of the most popular structural aluminum alloys today. A free-grained and similar mechanical characteristics of the alloy are incredibly perfect in precision manufacture applications that entail close tolerances and dependability.

What Is 7075 Aluminum?

The 7075 aluminium is a strong aluminium alloy which essentially comes alloyed with zinc and sometimes magnesium and copper in lesser amounts. This alloy is part of the 7xxx series and are usually tempered with a condition called T6 which gives the most strength. Being characterized by an outstanding strength-to-weight ratio, 7075 is commonly referred to as aircraft aluminum because of a broad application in the aerospace industry.

7075 aluminum was also developed in World War II to be used in aircraft purposes, but it has better strength properties with most of the other alloyed aluminum. This increased strength is however associated with compromises in other material properties like corrosion resistance and weldability and therefore choice of materials used in a particular application is very critical.

6061 vs 7075 Aluminum: In-depth Comparison

Chemical Composition

The principle distinction between these alloys is in their chemical component:

6061 Aluminum:

• Aluminum: 95.8-98.6%
• Magnesium: 0.8-1.2%
• Silicon: 0.4-0.8%
• 0.7max% of iron
• Copper: 0.15-0.40%
• Chromium: 0.04-0.35%
• Zinc: max 0.25 per cent
• Titanium 0.15 max

7075 Aluminum:

• Aluminum: 87.1-91.4%
• Zinc: 5.1-6.1%
• Magnesium: 2.1-2.9%
• Copper: 1.2-2.0%
• Chromium: 0.18-0.28%
• Iron: no more than 0.5%
• Silicon: max 0.4%
• Titanium: 0.2 % max

The increased amount of zinc in 7075 makes it have a better strength, whereas magnesium and silicon in 6061 have a superior property of resisting corrosion and workability.

Mechanical Properties

Between these alloys, there are quite several differences notably in the mechanical behavior:

6061-T6 Aluminum:

• TEnter Tonsile Strength: 290 MPa, or 42,000 psi
• Yield Strength: 240 MPa (35000 psi)
• Elongation: 12-17%
• Hardness: 95 HB
• Elasticity modulus: 68.9 gpa

7075-T6 Aluminum:

• Tensile strength: 572 MPa (83,000 psi)
• Strength of Yield: 503 MPa (73,000 psi)
• Elongation: 11%
• Hardness150 HB
• Modulus of Elasticity: 71.7 GPa

The strength of the 7075 aluminum is almost twice that of 6061 and thus, is good in high stress applications. Nevertheless, 6061 is superior in its ductility that is beneficial to its forming and bending processes.

Corrosion Resistance

One very important aspect in material selection may be corrosion resistance:

The magnesium and silicon component makes 6061 aluminum very resistant to corrosion. The alloy develops natural protection against corrosion, most of the environments covered by a protective oxide layer. It is not corroded easily in marine jungles and is good against stress corrosion cracking.

7075 Aluminum is less resistant to corrosion in comparison with the 6061, especially to stress corrosion cracking. Its composition of copper and zinc is higher so it tends towards galvanic corrosion. Protective coating or anodizing treatment may be needed on applications which require 7075.

Weldability

The ability of weldability plays a very important role in manufacture:

Aluminum 6061 has high weldability with several techniques at work such as TIG, MIG, and resistance welding. The alloy has acceptable strength to welded joints and has low cracking potential. FULL strength properties may be achieved in post-weld heat treatment.

7075 Aluminum contains high amounts of zinc; therefore it is challenging to weld resulting to hot cracking and porosity. Although welding can be performed it must be done with special techniques and fillers. The heat affected zone normally exhibits lower strength characteristics, which are not completely recoverable by means of the heat treatment.

Bearbeitbarkeit

Machinability impacts on the quality of production and surface finish:

Great machinability, chip and surface finish are obtainable with 6061 Aluminum. It can be machined easily with normal tooling and cutting parameters so the alloy is good towards precision parts that have tight tolerances such as connector mold parts.

Aluminum 7075 is easier to machine and it is more mechanically strong and, therefore, must have more attention paid to cutting parameters and tool choices. It can reach high surfaces finishes, but tool wear rates might be increased as compared with 6061.

Cost

Project economics are influenced by cost consideration:

The 6061 aluminum tends to be more economical since it has a simplified composition and has a broad availability. It is cost-effective since the raw material is cheaper and the material can be easily processed in many applications.

Aluminum Aluminum fetches a higher premium because of the increased alloy content and also manufacturing processes. Its extra strength is usually compensated with its superb strength characteristics in tough applications.

Weight

The two alloys have common weight properties:

6061 Aluminum: 2.70 g/cm 3 of density 7075 Aluminum: 2.81 g/cm 3 of density

The small difference in weight is not important in the majority of the applications and both alloys allow supreme strength to weight ratios in comparison to steel and other metals.

Anwendungen

Both the alloys are superior in different applications:

6061-T6 Aluminum Applications:

• Tooling and accuracy in mold parts
• Car connection coverings
• Part of medical devices
• The packaging of semiconductors Semiconductor packaging equipment
• General building uses
• Marine hardware
• Bikes, bicycle frames and components

7075 Aluminum Applications:

• Structural components of the aerospace
• Performance auto parts
• Military equipment
• Rock climbing equipment
• Stressful mechanical parts High-stress mechanical components
• Accurate tools that need strength

How to Choose Between 6061 and 7075 Aluminum

The choice of the suitable alloy of the aluminum will rely on some of the following important factors:

When:

• Only medium strength demands are needed
• Good resistance to corrosion is required
• It involves a welding requirement in application
• Economic efficiency of choice is of importance
• Formability and good machinability are significant
• The application includes marine or corrosive environment

Choose 7075 when:

• The first need is maximum strength
• The key to weight loss is essential
• The employment is associated with great stresses
• Corrosion resistance could be solved with coatings
• The price increase is purported by the performance advantage
• No welding is involved in this question or can be avoided

In precision mold construction, 6061-T6 has often been found to be the best combination of machinability, dimensional stability and economy, with 7075 being chosen when high-stressed tooling is a factor where maximum strength is required.

Schlussfolgerung

Both 6061-T6 and 7075 alloys of aluminum are useful in precision manufacturing. The selection between them must be done with an assessment of the strength requirements, environmental factors, design of manufacturing and cost requirements. This knowledge of differences helps engineers and industrialists in making base decisions to optimize the performance against the basic limitations of the project.

At the Dongguan Zecheng Precision Mold Co., Ltd. we are experienced in working with an assortment of aluminum alloys and in that regard we can offer recommendations and manufacture precision parts out of the most suitable material which fits your special application. We have very high precision Japanese made production equipment and up to date processing technology to obtain the close tolerance and premium finish needed on 6061-T6 and 7075 aluminum parts.