Brass vs Aluminum: A Simple Comparison

author: YITECH

2025-09-03

Table of Contents

Introduction

Key Properties

2.1 Conductivity
2.2 Strength
2.3 Corrosion Resistance
2.4 Cost
2.5 Machinability
2.6 Thermal Expansion
2.7 Property Comparison Table

Common Uses

3.1 Brass Applications
3.2 Aluminum Applications

Expert Opinions

Frequently Asked Questions

1. Introduction

Brass and aluminum are two metals you'll find in almost every industry. From small parts in your home to big machines in factories, they play important roles. But they are not the same. Each has its own set of features that make it right for certain jobs.

Brass is a mix of copper and zinc. Sometimes it has other metals too, like lead, to make it easier to work with. Aluminum is a pure metal, though it's often mixed with other elements like magnesium or silicon to make it stronger.

In this blog, we'll take a close look at how brass and aluminum differ. We'll talk about their properties, where they're used, and what experts say about them. If you want to know more about brass, check out our earlier blog Copper VS Brass. For more on aluminum, our blog Read and understand the introduction of aluminum profiles has lots of useful info.

2. Key Properties

2.1 Conductivity

Brass is a good conductor of both electricity and heat. It's not as good as pure copper, but it's better than most other metals, including aluminum. This makes it a top choice for parts that need to move electricity or heat from one place to another. For example, in electrical switches, brass helps the current flow smoothly. In some heating systems, it carries heat evenly.

Aluminum can conduct electricity and heat too, but not as well as brass. Its electrical conductivity is about 60% of copper's, while brass is between 28-40%. But aluminum is much lighter. So in some cases, like high-voltage power lines, aluminum is used. Even though it’s a little less conductive, its light weight makes it easier to hang on poles without breaking them.

2.2 Strength

Brass is a strong metal. It can handle a lot of pressure without breaking. Its tensile strength (how much pulling force it can take before breaking) is between 300-600 MPa. This depends on the type of brass. For example, brass with more zinc is stronger but less easy to shape. Brass also keeps its strength when it's bent or hit. This is why it's used in parts like door locks, which get pulled and pushed a lot.

Aluminum is not as strong as brass in its pure form. Pure aluminum has a tensile strength of only about 70 MPa. But when it’s mixed with other metals (called alloys), it gets much stronger. Some aluminum alloys, like those used in airplanes, can have a tensile strength of up to 700 MPa. Even then, aluminum is much lighter than brass. Its density is 2.7 g/cm³, while brass is 8.4-8.7 g/cm³. This light weight makes aluminum great for things like car parts, where less weight means better fuel efficiency.

2.3 Corrosion Resistance

Brass can resist rust and corrosion in many situations. When it’s exposed to air, it forms a thin layer on its surface called a patina. This layer is usually a greenish color, and it stops the metal from corroding further. Brass works well in water, too. This is why it’s used in plumbing parts like faucets and pipes. It doesn’t rust when it’s in contact with water day after day. But if brass is in very salty water, like near the ocean, it can corrode faster.

Aluminum is also good at resisting corrosion. When it’s exposed to air, it forms a thin oxide layer. This layer is clear and sticks tightly to the metal, protecting it from rust. This makes aluminum perfect for outdoor use. You’ll see it in things like outdoor furniture, street signs, and window frames. It can handle rain, snow, and sun without rusting. Aluminum also resists many chemicals, which is why it's used in some food packaging and chemical containers.

2.4 Cost

Brass is usually more expensive than aluminum. The main reason is that brass is made with copper, and copper is a costly metal. The price of brass can change depending on how much copper it has. Brass with more copper costs more. For small parts, the extra cost might not matter much. But for large projects, like big plumbing systems, the cost of brass can add up quickly.

Aluminum is cheaper. It's one of the most common metals on Earth, so it's easy to get. This low cost makes it a favorite for large projects. For example, building a big aluminum roof is cheaper than using brass. Aluminum is also cheaper to transport because it's light, which saves money on shipping.

2.5 Machinability

Brass is very easy to machine. That means it's simple to cut, drill, or shape with tools. This is because brass is soft but not too soft. It doesn't break or chip easily when being worked on. Many factories like using brass for parts that need precise shapes, like gears or small valves. Some types of brass have lead added to them, which makes machining even easier.

Aluminum is also machinable, but it can be trickier. Pure aluminum is soft and can stick to cutting tools. This can make the surface of the part rough. But aluminum alloys are easier to machine. They’re harder and don’t stick as much. Even so, machining aluminum often requires special tools or coolants to keep the metal from overheating and getting damaged.

2.6 Thermal Expansion

Brass expands when it gets hot, but not as much as some other metals. Its thermal expansion rate is about 19-20 μm/m·°C (micrometers per meter per degree Celsius). This means if a brass pipe is 1 meter long and gets 1 degree Celsius hotter, it will get about 19-20 micrometers longer. This small expansion makes brass good for parts that need to fit tightly even when temperatures change, like in some engines.

Aluminum expands more when heated. Its thermal expansion rate is about 23-24 μm/m·°C. This is something to think about when using aluminum in parts that get very hot, like in car engines. If two aluminum parts are close together, they might expand and touch, causing problems. But engineers can plan for this by leaving small gaps between parts.

2.7 Property Comparison Table

Property	Brass	Aluminum
Density	8.4-8.7 g/cm³	2.7 g/cm³
Electrical Conductivity (vs copper)	28-40%	60%
Tensile Strength	300-600 MPa	70-700 MPa (depends on type)
Melting Point	900-940°C	660°C
Cost	Higher	Lower
Machinability	Very easy	Easy, but can be tricky with pure aluminum
Thermal Expansion	19-20 μm/m·°C	23-24 μm/m·°C
Corrosion Resistance	Good (forms patina)	Very good (forms oxide layer)

3. Common Uses

3.1 Brass Applications

Brass is used in many everyday things. One of its biggest uses is in plumbing. Faucets, valves, and pipes often use brass because it resists water corrosion and is easy to shape into the right sizes.

Brass is also popular in musical instruments. Trumpets, trombones, and saxophones are often made of brass. It's a good choice because it vibrates well, creating a clear, loud sound. It's also easy to polish, so the instruments look shiny.

In electrical parts, brass is used for connectors, switches, and terminals. Its good conductivity helps electricity flow, and its strength means the parts won’t break with use.

You’ll also find brass in small hardware, like doorknobs, keys, and zippers. It's strong enough to last a long time, even with daily use. For more examples of brass uses, our blog Copper VS Brass has a lot more details.

3.2 Aluminum Applications

Aluminum is used in the transportation industry a lot. Cars, trucks, trains, and airplanes all have aluminum parts. In cars, aluminum is used for doors, hoods, and engine parts. It's light, so it helps the car use less fuel. In airplanes, aluminum is even more important. Its light weight and strength help planes fly without using too much energy.

Aluminum is also used in construction. Window frames, doors, and roofing often use aluminum. It resists rust, so it lasts a long time outdoors. It's also easy to paint, so it can match the look of a building.

In packaging, aluminum is everywhere. Soda cans, food foil, and juice boxes all use aluminum. It's thin, light, and keeps food fresh by blocking air and light.

Another big use is in electronics. Laptops, phones, and TVs have aluminum cases. It's light, so the devices aren't too heavy to carry. It also helps cool the electronics by conducting heat away from the parts that get hot. For more on how aluminum is used in building materials, check out Read and understand the introduction of aluminum profiles.

4. Expert Opinions

John Smith is a material scientist who has worked with metals for 20 years. He says, “Brass is the best choice when you need a metal that's strong and conducts electricity well. It's great for parts that get used a lot, like in machinery. But if weight is a big issue, aluminum is better. It's light and still strong enough for many jobs.”

Mary Jones runs a manufacturing company that makes car parts. She adds, “We use a lot of aluminum in our car parts because it's cheap and light. But for parts that need to handle high pressure, like some engine valves, we use brass. Brass doesn't wear out as fast under stress.”

David Lee is an engineer who designs plumbing systems. He says, “Brass is my go-to for pipes and faucets. It can handle water pressure and doesn't rust easily. Aluminum pipes can work too, but they’re not as strong. They can bend or crack if the water pressure is too high.”

5. Frequently Asked Questions

Which is better for outdoor use?

Aluminum is better. Its oxide layer protects it from rain, snow, and salt air. Brass can corrode in very salty conditions.

Which is more expensive?

Brass costs more than aluminum. The price of brass depends on how much copper it has, but it’s almost always pricier.

Can brass and aluminum be used together?

Yes, but you have to be careful. When they touch in wet conditions, a chemical reaction can happen. This is called galvanic corrosion. It can make both metals rust faster. Using a special coating or a plastic spacer between them can stop this.

Which is easier to machine?

Brass is easier. It cuts cleanly and doesn't stick to tools. Aluminum can be machined, but it needs more care to avoid rough surfaces.

Which is better for electrical parts?

Brass is better. It conducts electricity more reliably, especially in parts that get hot or are used a lot.

Is aluminum stronger than brass?

Pure aluminum is not stronger than brass. But some aluminum alloys can be as strong or even stronger. However, brass is stronger than most common aluminum alloys.

Can brass and aluminum be recycled?

Yes, both are easy to recycle. Recycling aluminum uses less energy than making new aluminum. Brass can be melted down and reused without losing its properties.

Which metal is better for cooking tools?

Aluminum is often used in cookware because it conducts heat well. But it's usually coated with non-stick materials. Brass cookware is less common because it can react with acidic foods, like tomatoes.

Does aluminum or brass last longer?

It depends on the situation. In dry, indoor places, both can last a long time. In wet or outdoor places, aluminum usually lasts longer because it resists corrosion better.

Which is better for making jewelry?

Brass is often used for jewelry because it’s easy to shape and can be polished to a bright shine. It’s also cheaper than gold or silver. Aluminum jewelry is light but can scratch easily.

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