Titanium and aluminum are both light metals that get specified to save weight, so they end up competing for the same aerospace, marine and high-performance jobs. The trade is clear once you line them up: aluminum is lighter and far cheaper, titanium is much stronger, holds heat, resists corrosion and survives fatigue. This page compares the two on weight, strength, temperature, corrosion, fatigue, cost and fabrication, and shows when each is the right call.
Weight and density
Aluminum wins on raw weight. Its density is about 2.7 g/cm3 against roughly 4.5 g/cm3 for titanium, so an aluminum part is about 40 percent lighter than the same part in titanium. If the only goal is the lightest possible part at low load and low temperature, aluminum is hard to beat. The reason titanium still gets chosen over aluminum is that raw density is only half the story; strength and the conditions the part has to survive decide the rest.
| Property | Titanium | Aluminium |
|---|---|---|
| Density | Roughly 4.5 g/cm3 | About 2.7 g/cm3, so an aluminium part is about 40 percent lighter |
| Tensile strength | Grade 5 (Ti-6Al-4V) reaches about 895 MPa | Roughly 310 MPa for 6061-T6, and about 572 MPa for 7075-T6 |
| Temperature | Grade 5 remains suitable for structural use well above aluminium’s range | Loses strength quickly above about 150 degrees C and is not used as a structural metal much past that |
| Corrosion | The stronger performer by a wide margin; its oxide film resists seawater, chlorides and most chemicals with no coating | Commonly protected by coating or anodising in those services |
Strength and strength-to-weight
Titanium is much stronger. Grade 5 titanium (Ti-6Al-4V) reaches about 895 MPa tensile, against roughly 310 MPa for 6061-T6 aluminum and about 572 MPa for the high-strength 7075-T6. On strength-to-weight, 7075 aluminum and Grade 5 titanium are close, but titanium carries far more absolute load for a given cross-section, so it lets a part be thinner and take more force. Where the load is high or the section has to stay small, titanium does what aluminum cannot.
Temperature
Heat separates them. Aluminum loses strength quickly above about 150 degrees C and is not used as a structural metal much past that. Grade 5 titanium keeps useful strength to around 400 degrees C and beyond, which is why titanium appears in engine and airframe areas that run hot while aluminum stays in the cooler structure. For any part that sees sustained heat, titanium is the metal that holds up.
Corrosion resistance
Titanium is the stronger corrosion performer by a wide margin. Its oxide film resists seawater, chlorides and most chemicals with no coating. Aluminum forms its own oxide and does well in mild conditions, but it pits in seawater, corrodes in alkaline and salty environments, and usually needs anodizing or paint for outdoor and marine service. In a corrosive or marine setting, titanium lasts where bare aluminum does not. The same corrosion case applies to stainless steel, covered in the titanium vs stainless steel comparison.
Fatigue and stiffness
Titanium handles cyclic load better. It has a fatigue endurance limit, a stress below which it can run almost indefinitely, while aluminum has no true fatigue limit and keeps accumulating damage under repeated loading until it cracks. Titanium is also stiffer, with a modulus near 105 GPa against about 69 GPa for aluminum, so it deflects less under load. For springs, rotating parts, fasteners and anything that flexes millions of times, titanium is the safer fatigue choice.
| Point | What the guide states |
|---|---|
| Fatigue and stiffness | Titanium handles cyclic load better. It has a fatigue endurance limit, a stress below which it can run almost indefinitely, while aluminium has no true endurance limit |
| Machining, forming and cost | Aluminium is cheaper to buy and far cheaper to machine, extrude and form; it cuts fast and shapes easily, which is a real part of its cost advantage |
| Galvanic pairing | When titanium and aluminium are joined in a wet, conductive environment, titanium is the more noble metal and the aluminium becomes the part that corrodes |
Machining, forming and cost
Aluminum is cheaper to buy and far cheaper to machine, extrude and form; it cuts fast and shapes easily, which is a real part of its cost advantage. Titanium costs more per kilogram, runs slower in the machine, needs sharp tools and good coolant, and demands inert gas shielding when welded. For a cost-driven part at mild conditions, aluminum is the economical answer. The extra titanium cost is paid back only when strength, heat or corrosion would push aluminum out.
| Point | What the guide states |
|---|---|
| Cost driver | Titanium costs more per kilogram, runs slower in the machine, needs sharp tools and good coolant, and demands inert gas shielding when welded |
| When the extra cost pays back | Only when strength, heat or corrosion would push aluminium out |
Mixing titanium and aluminum: galvanic notes
When titanium and aluminum are joined in a wet, conductive environment, titanium is the more noble metal and the aluminum becomes the part that corrodes faster. Titanium itself is unaffected. Aerospace assemblies that bolt titanium to aluminum manage this with sealants, coatings and isolation so the aluminum does not sacrifice itself to the couple. It is a detail worth catching whenever the two are designed into the same wet joint.
Which to choose
Choose aluminum when the part is cost-sensitive, runs cool, sees mild conditions and the lightest possible weight at low load is the goal. Choose titanium when the load is high, the service runs hot, the environment is corrosive or marine, or the part is fatigue-critical; in those cases titanium earns its higher price by lasting and by carrying more for its weight. Many designs use both, putting aluminum in the cool, low-load structure and titanium where heat, load, corrosion or fatigue would defeat it.
| Choose | What the guide states |
|---|---|
| Aluminium | When the part is cost-sensitive, runs cool, sees mild conditions and the lightest possible weight at low load is the goal |
Grades side by side
| Property | Ti Grade 2 (R50400) | Ti Grade 5 (R56400) | 6061-T6 aluminum | 7075-T6 aluminum |
|---|---|---|---|---|
| Tensile strength (min/typ) | 345 MPa | 895 MPa | ~310 MPa | ~572 MPa |
| Density | 4.51 g/cm3 | 4.43 g/cm3 | 2.70 g/cm3 | 2.81 g/cm3 |
| Useful temperature | to ~400 C | to ~400 C+ | fades above ~150 C | fades above ~150 C |
| Seawater corrosion | resists | resists | pits, needs coating | pits, needs coating |
| Relative cost per kg | higher | highest | lowest | low |
Common questions
Is titanium stronger than aluminum? Yes, by a large margin. Grade 5 titanium is about three times the tensile strength of 6061-T6 aluminum and well above 7075-T6, though aluminum is lighter per part.
Is titanium lighter than aluminum? No. Aluminum is about 40 percent lighter by density. Titanium wins on strength-to-weight at higher loads, not on raw weight.
Which is better for high temperature? Titanium. Aluminum loses strength above roughly 150 degrees C, while Grade 5 titanium stays useful to around 400 degrees C and beyond.
Which resists corrosion better? Titanium, clearly. It handles seawater and chlorides bare, while aluminum usually needs anodizing or paint and still pits in marine service.
Why is titanium more expensive than aluminum? Titanium is harder to extract, melt, machine and weld. The cost is paid back in strength, heat resistance, corrosion life and fatigue performance.
Can you bolt titanium to aluminum? Yes, but in wet service the aluminum corrodes as the less noble metal, so the joint needs isolation, sealant or coating.
Beiyu Titanium is the international titanium export brand of Jiaxing Beiyu New Materials Technology Co., Ltd., with production backing in Baoji, Shaanxi. When titanium is the better engineering choice, start with the required product form rather than the alloy name alone. Review Beiyu’s titanium material range, then send the grade, governing ASTM or AMS standard, dimensions, quantity, condition, application and required inspection-document scope to [email protected]. For grade selection, use the titanium grades comparison guide, the Grade 5 page and the Grade 2 page. If EN 10204 3.1 documentation or heat traceability is required, state the requested results and traceability fields so the available scope can be confirmed before order release.
Where the two materials stop being comparable on paper
A weight and strength comparison is easy to publish and hard to order from. The moment an aluminium part is redrawn in titanium, the acceptance basis changes, and the fields that decide whether the bar can be machined as delivered are not the fields the comparison discussed.
| Decided by the material choice | Still decided by the order |
|---|---|
| Density, stiffness and corrosion behaviour | Diameter tolerance, as a class or a value |
| Which grade suits the service | Straightness, with the gauge length it applies over |
| The governing product standard | Surface condition, stated apart from the delivery condition |
| Minimum mechanical properties | Examination scope and its acceptance class |
What Beiyu publishes on the precision ground bar route
For parts converted from aluminium the input is usually small diameter bar, so the published values on that route are the ones a machining quote depends on. They cover the documented centerless ground route from 3.175 mm to 25.4 mm diameter, as a production capability the order is reviewed against rather than a stock statement.
| Field | Published value |
|---|---|
| Diameter tolerance | ±0.0127 mm (±0.0005 in), tightened to ±0.0076 mm on request |
| Straightness | 0.5 mm per metre, and 0.3 mm per metre on diameters up to 25 mm |
| Examination | Ultrasonic, eddy current, optical surface, laser diameter and straightness, each at 100 percent of the lot |
| Certificate | EN 10204 3.1 mill test certificate with heat number traceability |
These controls belong to the quoted precision program and are not carried across to the full 1 mm to 500 mm round bar envelope.
For the absolute figures behind this comparison, density by titanium grade and weight per metre by size, see is titanium heavy.
Specification detail with sources
The titanium menu is wider than the two grades usually quoted against aluminum. ASTM B265 lists a minimum tensile strength of 620 MPa and a minimum yield strength of 483 MPa for annealed Grade 9, Ti-3Al-2.5V, the cold-workable intermediate alloy used for hydraulic tubing, which lands between commercially pure metal and Ti-6Al-4V on strength while forming more readily than the latter. The same standard sets elongation minimums of 20 percent for Grade 2 and 10 percent for Grade 5, numbers worth checking when a design is converted from a ductile aluminum temper.
| Grade | Minimum values the guide cites from ASTM B265 |
|---|---|
| Grade 9, Ti-3Al-2.5V, annealed | 620 MPa tensile and 483 MPa yield; the cold-workable intermediate alloy used for hydraulic tubing |
| Grade 2 | 20 percent minimum elongation |
| Grade 5 | 10 percent minimum elongation |
Melting behaviour anchors the temperature contrast with handbook values. ASM Handbook Volume 2 gives 660 C for the melting point of pure aluminum and a melting range of about 582 to 652 C for 6061, against roughly 1668 C for unalloyed titanium, so titanium operates much further from its melting point at any shared service temperature. On the specification side, aerospace Ti-6Al-4V sheet is ordered to SAE AMS 4911 in the annealed condition, while structural aluminum is ordered to ASTM B209 for sheet and plate and ASTM B221 for extrusions, each with temper-specific property tables.