Aluminum vs Brass vs Titanium: Weight, Hardness & Machinability Compared

Aluminum is softer than brass in most commonly used grades. Brass (C360) measures 100 to 120 HV on the Vickers hardness scale, while general-purpose aluminum (6061-T6) sits at 85 to 100 HV and pure aluminum (1100) drops to 25 to 35 HV. Titanium (Grade 5, Ti-6Al-4V) outperforms both at 300 to 370 HV, but at roughly 67% more weight than aluminum and several times the machining cost.

For engineers and sourcing managers selecting materials for CNC machining projects, the choice between aluminum, brass, and titanium comes down to five factors: how much the part can weigh, how hard the surface needs to be, how easily it machines, what environment it must survive, and what the budget allows. These three metals sit at very different points across all five dimensions.

This guide provides a complete side-by-side comparison with specific grades, hardness values, density figures, tensile strengths, machinability ratings, and cost context so you can match the right metal to the right application without guesswork.

Is Aluminum Softer Than Brass?

Yes. In most standard engineering grades, aluminum is softer than brass. Free-machining brass (C360/C36000) has a typical Vickers hardness of 100 to 120 HV, while the most widely used structural aluminum alloy (6061-T6) measures 85 to 100 HV. Pure aluminum grades like 1100 are significantly softer at just 25 to 35 HV.

However, there are important exceptions. Aerospace-grade aluminum 7075-T6 reaches 150 to 180 HV, which makes it harder than most standard brass alloys. Naval brass (C464) sits at 120 to 150 HV, placing it in the same range as high-strength aluminum. The answer to "is aluminum softer than brass" depends entirely on which specific alloy and temper you are comparing.

This matters for part design because hardness directly affects scratch resistance, wear life, and deformation under load. Brass components used in valve seats, bushings, and sliding-contact applications rely on their higher hardness for long-term dimensional stability. Aluminum parts that require surface hardness comparable to brass can achieve it through anodizing, which raises the surface to 200 to 600 HV depending on whether Type II or Type III hardcoat is specified. For a complete breakdown of anodizing types, identification tests, and how anodized aluminum compares to raw aluminum across every engineering property, see our companion guide on anodized aluminum vs raw aluminum.

Titanium Weight vs Aluminum Weight: Which Is Lighter?

Aluminum is significantly lighter than titanium. Aluminum has a density of approximately 2.70 g/cm³, while titanium (Ti-6Al-4V, Grade 5) has a density of approximately 4.50 g/cm³. That makes titanium roughly 67% heavier than aluminum for the same volume of material.

In practical terms, a 100 mm cube of aluminum weighs about 270 grams, while the same cube in titanium weighs about 450 grams. For parts where minimizing physical mass is the primary goal, aluminum is the clear winner. This is why aluminum dominates applications such as electronics enclosures, automotive body panels, drone frames, and general structural brackets where weight savings translate directly into performance or cost advantages.

Titanium's advantage emerges when you factor in strength. Because titanium is roughly 2 to 3 times stronger than most aluminum alloys at the tensile level, a titanium part can often be designed with thinner walls or less material to carry the same load. In those cases, the finished titanium part may weigh less than the aluminum equivalent even though the raw material is denser. This is the concept of strength-to-weight ratio, and it is the reason titanium remains competitive in aerospace manufacturing and high-performance applications despite its higher density and cost.

Complete Property Comparison: Aluminum vs Brass vs Titanium

The following table compares the most commonly specified grades of all three metals across every property that influences material selection for CNC-machined parts.

Sources: Material property data referenced from Thomas Publishing (6061 vs 7075), ASM MatWeb (Ti-6Al-4V), and Metal Supermarkets (Brass 360).

Hardness Comparison: How Aluminum, Brass, and Titanium Stack Up

Surface hardness determines how well a part resists scratching, indentation, and wear during service. The hardness of all three metals varies significantly by alloy grade and heat treatment condition.

The key takeaway: standard aluminum (6061-T6) is softer than standard brass (C360), but high-strength aluminum (7075-T6) can exceed the hardness of common brass grades. Titanium Grade 5 is the hardest of the three by a wide margin and is the clear choice when surface hardness and wear resistance are primary design requirements.

Weight Comparison: Density and Real-World Impact

Weight is often the deciding factor in material selection, especially in aerospace, automotive, consumer electronics, and portable equipment applications.

Brass is by far the heaviest of the three, at more than three times the weight of aluminum per unit volume. This limits brass to applications where its superior machinability, corrosion performance in water systems, electrical conductivity, or aesthetic appearance justify the weight penalty. Titanium sits in the middle at 1.64 times the weight of aluminum, but its much higher strength means titanium parts can often be designed with thinner cross-sections to partially offset the density difference.

For applications where weight reduction is the primary goal, aluminum is the default material. Meco machines aluminum across all common alloy families (6061, 7075, 5052, 2024) for extruded profiles, CNC-machined components, and die cast parts.

Machinability: Which Metal Is Easiest to CNC Machine?

Machinability determines how fast a part can be produced, how much tool wear occurs, and ultimately how much the finished part costs. Brass, aluminum, and titanium sit at very different points on the machinability spectrum.

Brass: The Machinability Benchmark

Free-machining brass (C360) is one of the easiest metals to machine and is often used as the baseline reference for machinability ratings. It produces short, well-broken chips, generates minimal tool wear, and delivers excellent surface finishes with standard carbide tooling. Cutting speeds can run high, cycle times are short, and dimensional accuracy is easy to maintain. This makes brass the preferred material for high-volume precision parts such as electrical connectors, fittings, valve bodies, and threaded components.

Aluminum: Fast, Light, and Cost-Effective

Aluminum machines very quickly, often faster than brass in terms of material removal rate due to its lower hardness. Cutting speeds for aluminum can reach several hundred meters per minute on modern CNC equipment. The primary machining challenge with aluminum is built-up edge (BUE), where the soft material welds to the cutting tool, causing poor surface finish and dimensional drift. This is controlled with sharp tooling geometry, proper coolant application, and appropriate feed rates. Despite this issue, aluminum remains one of the most cost-effective metals to CNC machine at volume. For a detailed breakdown of aluminum and brass machining costs, see Meco's guide on how much CNC machining costs.

Titanium: Difficult, Slow, and Expensive

Titanium is the most challenging of the three to machine. Its very low thermal conductivity (6.7 W/m·K versus 167 W/m·K for aluminum) means heat concentrates at the cutting edge rather than dissipating through the workpiece. This causes rapid tool wear, galling, and work hardening. According to ATI's Ti-6Al-4V data sheet, titanium tends to smear, gall, and weld to cutting tools during machining. Cutting speeds must be kept low, feeds must be carefully controlled, and rigid setups with strong clamping are essential. Expect titanium CNC machining costs to run 2 to 5 times higher than equivalent aluminum parts due to slower cycle times and higher tooling consumption.

When to Choose Each Metal: Application Decision Guide

The right material depends on the balance of performance requirements, environmental exposure, production volume, and cost constraints.

Strength-to-Weight Ratio: The Real Performance Metric

Raw weight and raw strength numbers in isolation can be misleading. The metric that engineers use to compare structural efficiency across different metals is the specific strength, also called the strength-to-weight ratio. It is calculated by dividing tensile strength by density.

The data shows that 7075-T6 aluminum and Ti-6Al-4V titanium have remarkably similar specific strength values. This is why 7075 aluminum is sometimes chosen over titanium for structural aerospace components where the design can accommodate the larger cross-section that aluminum requires. Brass has the lowest structural efficiency and is never chosen for load-bearing applications where weight matters.

Corrosion Resistance: How Each Metal Performs in Service

All three metals offer good corrosion resistance, but in very different environments and through different mechanisms.

Aluminum forms a thin natural oxide layer that protects it well in atmospheric conditions. When anodized, this layer becomes 1,000 to 10,000 times thicker, providing excellent protection against moisture, salt spray, and most industrial chemicals. However, aluminum is vulnerable to galvanic corrosion when in direct contact with dissimilar metals (especially copper, brass, or steel) in the presence of an electrolyte.

Brass resists corrosion very well in freshwater and marine environments due to the copper content that forms a protective patina. Brass is the standard material for plumbing fittings, marine hardware, and fluid-handling valves. Its main weakness is dezincification, where zinc leaches out of the alloy in certain water chemistries, leaving a porous and weakened copper structure.

Titanium is the clear winner for corrosion resistance in aggressive environments. It resists seawater, chloride solutions, body fluids, and many acids that would attack both aluminum and brass. This is why titanium is the standard material for surgical implants, offshore equipment, and chemical processing hardware.

Thermal and Electrical Conductivity: Choosing for Heat and Current

If the part needs to transfer heat or conduct electricity, aluminum is the strongest choice among the three. Aluminum's thermal conductivity of 167 W/m·K (6061) makes it the standard material for heat sinks, cooling plates, battery thermal management components, and electronics housings. Brass offers moderate thermal conductivity at 115 W/m·K and is used where a combination of heat transfer, corrosion resistance, and machinability is needed (such as heater blocks and nozzles). Titanium's thermal conductivity of just 6.7 W/m·K makes it a poor heat conductor and effectively rules it out for thermal management applications.

For electrical conductivity, aluminum and brass both perform well. Aluminum at 43% IACS is widely used in power transmission, bus bars, and electrical enclosures. Brass at 26% IACS is used for electrical connectors, terminals, and switch components where its combination of conductivity and machinability is valuable. Titanium at roughly 1% IACS is essentially non-conductive and is never selected for electrical applications.