Titanium vs Aluminum for Aerospace Brackets and Fittings

Updated October 14, 2026

Titanium vs aluminum side by side, with the source for every number

Ti-6Al-4V is roughly 60 percent denser than aluminum and roughly 60 percent stiffer, so the two materials land in nearly the same place on stiffness per pound. Titanium pulls ahead on strength per pound against 6061, roughly ties 7075-T6, and wins clearly on temperature, salt air and contact with carbon fiber. Values below are typical producer data unless marked minimum; they are for comparison, not design.

Sources by column: Ti-6Al-4V values are from the United Performance Metals Ti-6Al-4V data sheet (2026), except the yield, which is the 120,000 psi minimum named in the SAE titles of AMS 4911 and AMS 4928. 6061 values are from the Protolabs 6061-T651/T6 data sheet (2026). 7075 values and the letter ratings are from Continental Steel's 7075-T651 plate page. Stress corrosion ratings are from NASA MSFC-STD-3029 Revision A, and the specialty metals row is from DFARS 252.225-7009. Mixing a titanium minimum with aluminum typical values understates titanium slightly; for analysis use MMPDS allowables or the procurement spec minimum for the exact form and thickness.

Specific strength and stiffness: what the ratios actually say

On stiffness per pound the materials are a tie, so titanium only saves weight where strength, temperature or volume sizes the part. Dividing the table values gives these ratios:

Three practical readings follow:

• Strength-sized parts. A lug, clevis or fitting sized by yield or bearing strength can be about 45 percent lighter in titanium than in 6061, but only slightly lighter than in 7075-T6. Against 7075-T7351, which runs about 63 ksi typical yield according to a producer page for AMS 4078 plate, titanium's margin grows again.
• Stiffness-sized parts. A bracket sized by deflection or natural frequency weighs about the same in either metal, because modulus per pound is equal. Converting such a part to titanium buys cost, not weight.
• Thin walls and panels. Where buckling or plate bending governs at a fixed weight, aluminum's lower density lets the wall be about 1.6 times thicker, and bending stiffness rises with thickness cubed. That is why enclosures, skins and thin webs stay aluminum.

Titanium earns its weight savings in compact, highly loaded parts where envelope is fixed, and in any part that also needs temperature or corrosion capability aluminum cannot give. The titanium alloys page covers grade and condition choices, and 6061 vs 7075 covers the aluminum side, so neither is repeated here.

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Temperature capability

Titanium holds useful strength to several hundred degrees Fahrenheit above the point where heat treated aluminum starts to lose temper. United Performance Metals states Ti-6Al-4V can be used from cryogenic temperatures to about 800 F, with acceptable oxidation resistance up to 1000 F, and gives a melting point of 3200 F. Protolabs gives 6061 a melting range of 1080 to 1206 F.

The bigger aluminum issue is not melting but overaging. Tempers such as T6 and T651 are produced by artificial aging, so sustained heat continues that process and lowers strength. That effect is old news to the industry: Alcoa engineers measured the tensile properties of 6061-T6 rod and 7075-T6 extrusions after 100 and 200 hours at 300 F and 400 F, both continuous and intermittent, in a study published as NACA TM-1419 in 1956. For any aluminum part that sees sustained heat, design to elevated temperature allowables with exposure time, not room temperature numbers.

• Brackets near engines, exhaust, heaters or plume heating: titanium is the usual answer, or a nickel alloy when titanium's limit is passed; see nickel superalloys.
• Cryogenic service: both metals are used. Ti-6Al-4V ELI is common for cryogenic fittings, covered in Ti-6Al-4V vs ELI, while welded aluminum tankage often uses 2219, covered on the aluminum alloys page.
• Thermal paths: 6061 conducts about 167 W/m K. Where a bracket is also a heat path, aluminum is often chosen for that reason alone.

Galvanic compatibility with carbon fiber

Titanium can sit against carbon fiber composite with modest sealing; aluminum must be isolated from it. In the seawater galvanic series in MIL-STD-889C (August 2016) Table II, graphite is listed at the noble, cathodic end, the titanium alloy entries, including Ti-6Al-4V annealed and aged, sit just above it with only AM350 (passive), silver and gold between them, and the aluminum alloys, including 6061-T6 and 7075-T6, sit near the active, anodic end. The further apart two materials are in the series, the faster the more active one corrodes when moisture bridges the joint, Carbon fiber composites conduct through the fibers and are generally treated like graphite in this ranking.

What the standard asks for when a couple cannot be avoided, in section 5.2:

• Arrange the couple so the cathode area is smaller than the anode area.
• Put a compatible metallic washer or gasket between the members, or plate the cathodic member, where the joint must conduct.
• Use an inert, non-absorbing gasket or washer where it need not conduct.
• Seal all faying edges, wet-install fasteners with corrosion inhibiting compound, and coat the outside of the joint.

Section 5.1.5 also names carbon loaded resin materials among non-metallics that will start corrosion of metals they are joined to. In practice an aluminum fitting bonded or bolted to a CFRP panel needs an isolation ply, commonly glass fabric, plus sealant and coated fasteners, and it still has to be inspected for corrosion over its life. A titanium fitting avoids most of that. Appendix A of the same standard lists titanium treatments that include use bare with faying edges sealed in contact with metals other than magnesium, zinc or cadmium, for electrical or thermal conducting purposes. The current revision is MIL-STD-889D, validated in April 2026; confirm the current revision on ASSIST before relying on any table.

Corrosion and stress corrosion in salt air

Ti-6Al-4V needs no finish for corrosion in coastal air, while aluminum needs a finish system and, for 7075, a resistant temper. MSFC-STD-3029 lists Ti-6Al-4V in Table I, high resistance to stress corrosion cracking in sodium chloride environments, in all conditions. 6061 is Table I in all tempers. 7075-T6 is Table III, low, and 7075 in the T73 class is Table I.

General corrosion follows the same order. Continental Steel rates 7075 C for general corrosion, and its footnote says C rated alloys should generally be protected at least on faying surfaces. Titanium still has limits: United Performance Metals warns that stress corrosion cracking may occur if chlorine salts are left on stressed parts that are later heated, so parts should be clean before heat treatment or hot service. Finish detail for aluminum is on the anodizing and chemical conversion coating pages.

Machinability and processing differences

Aluminum is cut many times faster than titanium, so the same geometry costs more spindle hours in titanium. United Performance Metals rates Ti-6Al-4V at 22 percent of B1112 with a typical stock removal rate of 30 surface feet per minute; 7075-T651 carries a B rating on Continental's A to E scale, and aluminum parts are usually limited by distortion rather than tool life.

• Thin features. Titanium's higher modulus helps, but its slow cutting means deep pockets and thin webs take long cycles. Pocketing a titanium part to the same wall as an aluminum design is where the hours go.
• Threads and wear. Titanium galls against itself and against stainless, so threaded titanium parts usually need a dry film lubricant or a coating on one member; see dry film lubricants. Aluminum threads in service usually get an insert; see helical coil vs key locking inserts.
• Heat treatment and surface. Titanium heated in air forms alpha case that must be removed; aluminum re-heat treatment distorts parts. Both go through a controlled heat treatment spec.
• Welding. 6061 welds well and titanium welds with full inert shielding; 7075 is machined and fastened. Procedures are on the sheet metal and welding page.
• Forming. Annealed Ti-6Al-4V is difficult to form at room temperature; ATI's data sheet for the ELI grade describes severe forming at temperatures up to 1,200 F. Aluminum brackets are routinely brake formed.

Cost and availability drivers

Titanium parts cost more because the stock costs more, more of it becomes chips, and every chip is cut slowly. We do not quote material prices; these are the drivers that separate the two quotes:

• Buy to fly ratio. A 2016 TWI paper on titanium aerostructures states the buy to fly ratio for machined titanium structure can be as poor as 20:1 and is rarely as good as 4:1. Paying for that much expensive material and removing it slowly is the main cost gap on hogged fittings.
• Specialty metals rules. DFARS 252.225-7009 treats all titanium as a specialty metal, so on contracts carrying the clause the melt source must be compliant. Aluminum is not a specialty metal under the clause, though contracts can carry other origin terms.
• Market breadth. 6061 and 7075 plate and bar serve many industries and are widely stocked. Titanium plate and bar in certified aerospace specs comes from fewer producers, and thick or unusual sizes can mean waiting for mill product.
• Processing steps. Titanium adds alpha case control, anti-galling treatments and slower inspection of hard-to-fixture parts. Aluminum adds anodize or conversion coat and, near carbon fiber, isolation and sealant.
• Certified remnants. Certified drops and surplus plate with traceable mill certs can shorten lead time on small parts in either metal, if the cert spec and condition match the drawing.

Choose titanium when, choose aluminum when

Choose titanium when the part is weight critical and strength, heat, salt or carbon fiber contact is the limiting factor. Choose aluminum when the part is cost critical, stiffness limited, thin walled, welded at low cost, or a heat path.

Choose Ti-6Al-4V when

• The part bonds or bolts directly to carbon fiber structure and isolation would be hard to inspect or maintain.
• Service temperature is beyond what an aluminum temper tolerates, up to the roughly 800 F the producer states.
• Strength sizes a compact part with a fixed envelope, such as a lug, end fitting or highly loaded clevis.
• The part sits in coastal air under sustained stress and you want a Table I material with no finish dependence.
• Cryogenic fracture toughness matters, using the ELI grade.

Choose aluminum when

• Stiffness, natural frequency or buckling sizes the part.
• The part is an enclosure, panel, thin web or formed bracket.
• It is GSE, tooling, a fixture or a frame where cost, lead time and weldability dominate.
• It must conduct heat or provide an electrical bond path.
• Quantities are high or schedules short and the extra mass is acceptable to the program.

Typical brackets and fittings and the usual choice

Most programs end up with both metals, sorted by interface and load. These are common patterns, not rules; your stress and materials engineers decide.

If the part touches oxygen, settle material compatibility first; titanium's oxygen limits are discussed on the titanium alloys page.

Callout examples for the drawing or PO

Name alloy, condition, form, spec and any isolation or finish requirement, so the part arrives ready to install against its mating structure.

• CFRP interface fitting: MATL: TITANIUM ALLOY 6AL-4V, ANNEALED, BAR PER AMS 4928. SURFACES FREE OF ALPHA CASE. INSTALL WITH FAYING SURFACE SEALANT PER the program sealant spec. Add the anti-galling treatment if threaded.
• Machined titanium bracket from plate: MATL: TITANIUM ALLOY 6AL-4V, ANNEALED, PLATE PER AMS 4911. Add DFARS 252.225-7009 compliance on the PO when the contract carries the clause.
• Aluminum bracket on metallic structure: MATL: AL ALLOY 6061-T651 PLATE PER AMS 4027. FINISH PER MIL-DTL-5541 TYPE II CLASS 3 where a bond path is required.
• Aluminum fitting that must touch CFRP: MATL: AL ALLOY 7075-T7351 PLATE PER AMS 4078. Isolate from composite with a glass fabric ply or inert gasket and seal faying edges, as the drawing defines, in line with MIL-STD-889 section 5.2.

Confirm the current revision of each spec on ASSIST or SAE before release. On the PO, require mill certs with heat number, chemistry (for titanium including hydrogen and oxygen) and tensile results to the named spec; our certs and traceability guide lists the full package, and stock forms are on plate and sheet and bar and rod.

Get titanium or aluminum material and parts quoted

Send the alloy, condition, spec, form and size through a certified material request, or attach the drawing if you want it machined. We source plate and bar with traceable mill certs from qualified suppliers, check that the cert spec, condition and melt source match your callout, and can put the material and the machining on one PO. If the choice between the two metals is still open, say so; we can ask for quotes in both so the cost gap is on paper before the design freezes. For export controlled drawings, follow our controlled programs process. Back to the materials hub.

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Questions

Related

• Titanium Alloys for Aerospace Hardware
• Aerospace Aluminum Alloys and Tempers
• 6061 vs 7075 Aluminum for Aerospace Parts
• Ti-6Al-4V vs Ti-6Al-4V ELI (Grade 5 vs Grade 23)

Sources

• United Performance Metals, Ti-6Al-4V data sheet (AMS 4911, 4928), 2026: density, modulus, service temperature, machinability
• Protolabs, Aluminum 6061-T651/T6 material data sheet (2026)
• Continental Steel, 7075-T651 aluminum plate properties and ratings
• DLA ASSIST, MIL-STD-889 document history (Revision C August 2016, Revision D July 2021, Notice 1 April 2026)
• MIL-STD-889C, Dissimilar Metals (22 August 2016), Table II galvanic series, sections 5.1.5 and 5.2, Appendix A
• NASA MSFC-STD-3029 Revision A, stress corrosion Tables I and III
• NASA NTRS, NACA TM-1419 (1956): intermittent vs continuous heating of 2024-T4, 6061-T6 and 7075-T6
• TWI, Linear Friction Welding of Ti 6Al 4V for Aerostructure Applications (2016), buy to fly ratios
• ATI, Ti-6Al-4V ELI technical data sheet: forming temperature
• Referans Metal, AMS 4078 7075-T7351 plate typical properties
• DFARS 252.225-7009 specialty metals
• SAE AMS 4928, Ti-6Al-4V bars, forgings and rings, annealed, 120,000 psi yield
• SAE AMS 4911, Ti-6Al-4V sheet, strip and plate, annealed