MIL-T-9046 - Ti-5Al-2.5Sn Titanium Sheet, Strip & Plate
MIL-T-9046 is a United States Department of Defense military specification for titanium and titanium alloy sheet, strip, and plate.
Originally issued in 1955, MIL-T-9046 was developed to standardize titanium flat-rolled products across multiple alloy compositions for use in U.S. military aircraft and defense systems.
The specification covers approximately 20 titanium alloy types within a single document – including commercially pure grades, alpha alloys such as Ti-5Al-2.5Sn, and alpha-beta alloys – which has historically caused confusion for procurement teams working from heritage engineering drawings.
MIL-T-9046 was scheduled for cancellation beginning in 1999 to transition to alloy-specific SAE Aerospace Material Specifications (AMS).
If your program or drawing calls out MIL-T-9046, contact us with the alloy composition and revision letter so we can source the correct material to specification requirements.
What Is MIL-T-9046?
MIL-T-9046 is a United States Department of Defense military specification for titanium and titanium alloy sheet, strip, and plate.
Originally issued in 1955, MIL-T-9046 was developed to standardize titanium flat-rolled products across multiple alloy compositions for use in U.S. military aircraft and defense systems.
The specification covers approximately 20 titanium alloy types within a single document – including commercially pure grades, alpha alloys such as Ti-5Al-2.5Sn, and alpha-beta alloys – which has historically caused confusion for procurement teams working from heritage engineering drawings.
MIL-T-9046 was scheduled for cancellation beginning in 1999 to transition to alloy-specific SAE Aerospace Material Specifications (AMS).
If your program or drawing calls out MIL-T-9046, contact us with the alloy composition and revision letter so we can source the correct material to specification requirements.
What Alloy Types Does MIL-T-9046 Cover?
MIL-T-9046 covers approximately 20 different titanium alloy types and conditions within a single specification document.
This breadth was intentional for the 1950s-era DoD standardization effort, but it creates challenges for modern procurement because a single “MIL-T-9046” callout on a drawing does not identify the specific alloy or condition.
When working with a drawing that calls out MIL-T-9046, engineers must also specify:
which titanium alloy is required (e.g., Ti-5Al-2.5Sn, CP Ti, Ti-6Al-4V, etc.)
annealed, cold-rolled, or other applicable condition
the specific revision of MIL-T-9046 applicable to the program
Applications of MIL-T-9046 Titanium
Aerospace & Defense Applications
The Ti-5Al-2.5Sn alloy covered by MIL-T-9046 has been used in sheet and plate form in:
- Jet engine casings and rings : excellent elevated-temperature properties and weldability make this alloy suitable for gas turbine structural components
- Aircraft structural skins and panels: sheet products for fuselage and airframe structures where weight reduction is critical
- Aerospace bulkheads and structural plates: plate products for primary and secondary aircraft structure
- Cryogenic fuel tanks: (ELI grade) – Ti-5Al-2.5Sn ELI retains ductility at liquid hydrogen and liquid oxygen temperatures, making it suitable for cryogenic tank and pressure vessel fabrication
- Military aircraft structures: used in a wide range of U.S. military aircraft programs during the period when MIL-T-9046 was the active specification
- Defense hardware assemblies: titanium sheet and plate components for military systems requiring corrosion resistance and elevated-temperature performance
MIL-T-9046 Chemical Composition Requirements - Ti-5Al-2.5Sn
MIL-T-9046 specifies chemical composition limits for each alloy type covered within the document. The following table shows the composition limits for Ti-5Al-2.5Sn in standard and ELI grades as required by MIL-T-9046 and carried forward in the current AMS successor specifications:
| Element | Symbol | Standard Grade (AMS 4910) | ELI Grade (AMS 4909) |
|---|---|---|---|
| Aluminum | Al | 4.0–6.0% | 4.0–6.0% |
| Tin | Sn | 2.0–3.0% | 2.0–3.0% |
| Iron | Fe | 0.50% max | 0.25% max |
| Oxygen | O | 0.20% max | 0.12% max |
| Carbon | C | 0.08% max | 0.08% max |
| Nitrogen | N | 0.07% max | 0.07% max |
| Hydrogen | H | 0.015% max | 0.0125% max |
| Other (each) | - | 0.10% max | 0.10% max |
| Other (total) | - | 0.40% max | 0.40% max |
| Titanium | Ti | Balance | Balance |
Aluminum stabilizes the alpha phase and increases strength at elevated temperatures. Tin contributes solid-solution strengthening without reducing weldability, which is why Ti-5Al-2.5Sn is preferred over alpha-beta alloys like Ti-6Al-4V when weldability is a critical design requirement.
Mechanical Properties - MIL-T-9046 Ti-5Al-2.5Sn Sheet, Strip & Plate
Minimum mechanical properties for Ti-5Al-2.5Sn sheet, strip, and plate in the annealed condition per the applicable AMS successor specifications:
| Property | Standard Grade (AMS 4910) | ELI Grade (AMS 4909) |
|---|---|---|
| Tensile Strength (min) | 115 ksi (793 MPa) | 110 ksi (758 MPa) |
| Yield Strength, 0.2% offset (min) | 100 ksi (690 MPa) | 95 ksi (655 MPa) |
| Elongation in 2 in. (min) | 8% | 10% |
The ELI grade’s higher minimum elongation requirement reflects its application in crack-sensitive structures and cryogenic environments where ductility and fracture toughness are more critical than peak tensile strength.
MIL-T-9046 Physical Properties - Ti-5Al-2.5Sn Sheet & Plate
| Property | Value (Imperial) | Value (Metric) |
|---|---|---|
| Density | 0.162 lb/in³ | 4.48 g/cm³ |
| Weight vs. Steel | ~58% the weight of steel | ~58% the weight of steel |
| Modulus of Elasticity | 15.9 × 10⁶ psi | 110 GPa |
| Continuous Service Temperature | Up to 896°F | Up to 480°C |
| Phase Classification | Alpha (single phase) | Alpha (single phase) |
| Heat Treatable? | No | No |
Important clarification
MIL-T-9046 vs AMS-T-9046:
MIL-T-9046 (issued by the U.S. Department of Defense) and AMS-T-9046 (issued by SAE International) are two separate but companion specifications addressing the same product forms. They are not the same document.
AMS-T-9046 was the SAE version developed in parallel with, and eventually superseding, the MIL-T-9046 designation.
Today, both have been superseded by alloy-specific AMS specifications such as AMS 4909 and AMS 4910 for Ti-5Al-2.5Sn sheet and plate.
What Replaced MIL-T-9046?
MIL-T-9046 was superseded by individual alloy-specific SAE Aerospace Material Specifications.
The table below shows the primary AMS replacements for the titanium types most commonly ordered against MIL-T-9046 in sheet, strip, and plate form:
| Alloy Type (MIL-T-9046) | Common Name | AMS Replacement — Sheet, Strip & Plate |
|---|---|---|
| Ti-5Al-2.5Sn (standard) | Grade 6 Titanium | AMS 4910 |
| Ti-5Al-2.5Sn ELI | Grade 6 ELI Titanium | AMS 4909 |
The AMS replacement specifications carry forward the composition and property requirements of MIL-T-9046 while adding enhanced testing, documentation, and qualification requirements aligned with modern AS9100-certified aerospace supply chains.
MIL-T-9046 vs MIL-T-9047 Key Difference
MIL-T-9046 and MIL-T-9047 are companion military specifications covering different product forms of the same titanium alloy families. They are not interchangeable:
| Characteristic | MIL-T-9046 | MIL-T-9047 |
|---|---|---|
| Product Forms Covered | Sheet, Strip, and Plate | Bars, Billets, and Forgings |
| Issuing Body | U.S. Department of Defense | U.S. Department of Defense |
| First Issued | 1955 | 1955 |
| SAE Counterpart | AMS-T-9046 | AMS-T-9047 |
| Primary AMS Replacements | AMS 4909, AMS 4910 | AMS 4924, AMS 4926, AMS 4966 |
| Cancellation | Scheduled 1999 | Scheduled 1999 |
If your drawing calls out MIL-T-9046, the required product form is sheet, strip, or plate.
If it calls out MIL-T-9047, the required product form is bar, billet, or forging.
MIL-T-9046 and Ti-5Al-2.5Sn - Why This Alloy?
MIL-T-9046 covers approximately 20 titanium alloy types in a single document.
On this site it is catalogued under the Ti-5Al-2.5Sn & ELI section because Ti-5Al-2.5Sn (ASTM Grade 6) is the alloy most commonly procured against MIL-T-9046 for U.S. military aerospace sheet and plate applications.
The composition, mechanical property, and material requirements shown on this page reflect MIL-T-9046 as it applies to Ti-5Al-2.5Sn sheet, strip, and plate.
For full alloy data, see the Ti-5Al-2.5Sn & ELI hub page
Why Ti-5Al-2.5Sn Is Preferred for Welded Structures
Ti-5Al-2.5Sn’s all-alpha microstructure provides superior weldability compared to alpha-beta alloys such as Ti-6Al-4V.
In welded structures, the heat-affected zone of an alpha alloy retains adequate strength and ductility without requiring a post-weld stress relief heat treatment to restore weldment properties – a significant fabrication advantage for assembled aircraft structures.
Weldability : MIL-T-9046 Ti-5Al-2.5Sn Sheet & Plate
MIL-T-9046 covers Ti-5Al-2.5Sn, one of the most weldable titanium alloys due to its single-phase alpha microstructure.
Key welding considerations for MIL-T-9046 material in sheet and plate form:
- TIG (GTAW): Primary process; argon shielding required for weld pool, back purge, and trailing shield
- MIG (GMAW): Used for higher deposition rates with inert shielding
- Electron Beam (EBW): Used in vacuum environments for critical aerospace welds
- Post-weld heat treatment: Not required for strength recovery in most applications – a significant advantage over alpha-beta alloys
- Shielding requirement: Titanium welds must be shielded with inert gas (argon or helium) until the weld and heat-affected zone cool below approximately 400°F (204°C) to prevent oxygen and nitrogen embrittlement
- No transformation hardening: The alpha microstructure does not undergo phase transformation during cooling, so there is no hardened HAZ requiring tempering
Safe Handling of MIL-T-9046 Titanium Sheet and Plate
Titanium sheet and plate in bulk form are safe to handle under normal conditions. Finely divided titanium presents fire and explosion hazards:
- Titanium chips, grinding dust, and fine turnings can ignite above 480°F (250°C) – and in some conditions at lower temperatures if very finely divided
- Use non-chlorinated cutting fluids only – chlorinated fluids can cause stress corrosion cracking in titanium
- Avoid accumulation of chips and fines in machining areas
- Store titanium chips and turnings in closed metal containers
- Use Class D (metal fire) extinguishers for titanium chip/powder fires
- Dry salt (sodium chloride) can smother titanium fires
Do not use water on burning titanium – water can sustain or intensify titanium fires
How to Order MIL-T-9046 Material
MIL-T-9046 is a superseded specification. When sourcing material against a legacy drawing or program requirement that calls out MIL-T-9046, the following information is needed to source correctly:
which of the ~20 alloy types within MIL-T-9046 is required (e.g., Ti-5Al-2.5Sn, Ti-6Al-4V, CP Ti Grade 2, etc.)
annealed or other condition as specified
the specific revision of MIL-T-9046 applicable to your program
thickness, width, and length (sheet) or thickness and width (plate/strip)
whether material must be certified to the original MIL-T-9046 requirements or to the current AMS equivalent
Fighter Jet Metals can source titanium sheet, strip, and plate to current AMS specifications (AMS 4909, AMS 4910) with documentation showing equivalency to MIL-T-9046 requirements where permitted by program requirements. Contact us with your specification details.
Cross-Reference Specifications for MIL-T-9046
SAE AMS - Ti-5Al-2.5Sn Sheet, Strip & Plate
These are the primary current AMS replacements for MIL-T-9046 in the Ti-5Al-2.5Sn alloy family. Both cover titanium sheet, strip, and plate in the annealed condition and are the standard procurement specifications for new programs.
SAE/Military - Companion Specification
AMS-T-9046 is the SAE International counterpart to MIL-T-9046. Both specifications address the same product forms (titanium sheet, strip, and plate) but were issued by different bodies — the DoD (MIL-T-9046) and SAE International (AMS-T-9046). AMS-T-9046 eventually superseded the MIL designation as the DoD transitioned responsibility for materials standards to SAE.
Boeing Material Specifications (DMS)
McDonnell Douglas / Boeing DMS material specification for Ti-5Al-2.5Sn sheet, strip, and plate. Proprietary Boeing document originating from the Long Beach facility.
MIL-T-9046 Trade Names & Equivalent Designations
MIL-T-9046 and the Ti-5Al-2.5Sn alloy it covers are referenced under several designations across different standards systems:
The AMS replacement specifications carry forward the composition and property requirements of MIL-T-9046 while adding enhanced testing, documentation, and qualification requirements aligned with modern AS9100-certified aerospace supply chains.
| Designation | System | Notes |
|---|---|---|
| Ti-5Al-2.5Sn | Common alloy name | Most widely used international notation |
| Grade 6 Titanium | ASTM designation | Per ASTM B265 sheet/strip classification |
| ASTM Grade 6 | ASTM formal | Used in ASTM specifications for sheet/plate |
| UNS R54520 | UNS (Unified Numbering System) | Standard material identifier in North America |
| Alpha Titanium | Phase classification | Describes single-phase microstructure |
| Ti-5-2.5 | Shorthand | Used in aerospace sourcing and engineering |
| 5Al-2.5Sn | Composition shorthand | Common in aerospace procurement documents |
| Ti-5Al-2.5Sn ELI | ELI variant | Extra Low Interstitial - tighter O, Fe, N, H limits |
| AMS 4909 | SAE specification | Current AMS equivalent for ELI sheet/plate |
| AMS 4910 | SAE specification | Current AMS equivalent for standard sheet/plate |
Why Source MIL-T-9046 from Fighter Jet Metals?
Legacy program expertise
MIL-T-9046 is a superseded specification. We understand how to source material to legacy program requirements and provide documentation showing equivalency to current AMS standards where applicable
Full mill certifications on every order
heat number, lot number, chemical analysis, and mechanical test certifications provided with each shipment
Complete heat-lot traceability
full chain of custody from mill to delivery
Aerospace-grade sourcing
material from AS9100-certified mills only
OEM specification support
supply to Boeing DMS 1568 and other OEM requirements that reference Ti-5Al-2.5Sn sheet and plate
Rapid quote response
competitive pricing with same-day quote turnaround
Custom processing
shearing, saw cutting, and custom sizing available
Certified Material for Critical Service
Aerospace programs demand strict adherence to recognized material standards and OEM specifications. Fighter Jet Metals supplies 5Al-2.5Sn & ELI titanium in accordance with AMS, MIL, and major aerospace company specifications, including those used by Boeing and other aerospace manufacturers.
All material is delivered with full mill certification, heat-lot traceability, and supporting documentation to meet the quality and compliance requirements of aerospace, defense, and high-performance industrial programs.