Titanium Ti-6Al-5Zr-0.5Mo
EN 3.7155
Ti-6Al-5Zr-0.5Mo (material number 3.7155) is a near-alpha titanium alloy developed in Germany for moderate elevated-temperature aerospace structure, combining weldability with good creep resistance.
Reference datasheet — Ti-6Al-5Zr-0.5Mo is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the BSTA condition
Ti-6Al-5Zr-0.5Mo tempers and conditions
Ti-6Al-5Zr-0.5Mo is supplied in 4 conditions, soft to hard. BSTA is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
BSTA | Used for thick discs and forgings where oil quenching is impractical; coarser transformed-beta gives slightly lower strength but the highest toughness and creep resistance. | 860 | 990 | 9 | 32 HRC | 1.1 % IACS |
Stress relieved | Applied to weldments and machined parts to remove residual stress without changing the transformed-beta structure; small drop in strength, slight ductility gain. | 870 | 990 | 11 | 32 HRC | 1.1 % IACS |
Annealed | Equiaxed/bimodal structure for bar and sheet: better ductility, low-cycle fatigue and formability, but noticeably lower creep resistance and toughness than the beta-treated condition. | 880 | 1,000 | 13 | 32 HRC | — |
BSTADefault Beta solution treated (≈1050 °C), oil quenched + aged 550 °C/24 h | Standard aerospace supply condition: basket-weave transformed-beta structure giving the best creep and fracture toughness at 450–520 °C. | 900 | 1,030 | 10 | 34 HRC | — |
What is Ti-6Al-5Zr-0.5Mo?
Ti-6Al-5Zr-0.5Mo (material number 3.7155) is a near-alpha titanium alloy developed in Germany for moderate elevated-temperature aerospace structure, combining weldability with good creep resistance. It is supplied beta solution treated and aged, beta STA air cooled, annealed or stress relieved, giving 900 MPa yield, 1030 MPa tensile, 10 % elongation and 34 HRC with service to 520 °C. Machinability is low (rating 17) and cold forming is limited to gentle bends, so parts are hot worked in the 900-1000 °C range. Ti-6Al-4V is the nearer alternative where the 520 °C capability is not needed. Ti-6Al-5Zr-0.5Mo has a density of 4.45 g/cm³ (0.161 lb/in³), lighter than 81% of titanium grades. It melts at 1,620°C (2,948 °F). Ti-6Al-5Zr-0.5Mo has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 82% of titanium grades. Elongation at break is 10% and the elastic modulus is 120 GPa (17.4 Msi).
What is Ti-6Al-5Zr-0.5Mo used for?
- Aero-engine casings
- High-temperature airframe structure
- Compressor discs and rings
- Welded engine ducting and manifolds
- Beta-forged rotating hardware
- Hot-section brackets and mounts
Advantages
- Stiff — 120 GPa (17.4 Msi), better than 98% of titanium grades
- High service temperature — 520°C (968 °F), better than 97% of titanium grades
- High strength — 900 MPa (131 ksi), better than 82% of titanium grades
Limitations
- Limited ductility — 10%, worse than 93% of titanium grades
- Difficult to weld — 65/100, worse than 77% of titanium grades
Ti-6Al-5Zr-0.5Mo properties
Typical room-temperature values for Ti-6Al-5Zr-0.5Mo-BSTA; bars are the position among titanium grades.
Physical3
Ti-6Al-5Zr-0.5Mo has a density of 4.45 g/cm³ (0.161 lb/in³), lighter than 81% of titanium grades. It melts at 1,620°C (2,948 °F).
Mechanical16
Ti-6Al-5Zr-0.5Mo has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 82% of titanium grades. Elongation at break is 10% and the elastic modulus is 120 GPa (17.4 Msi).
Thermal6
Ti-6Al-5Zr-0.5Mo is rated for continuous service to 520°C (968 °F). It conducts heat at 7 W/m·K (4.04 BTU/hr·ft·°F), worse than 76% of titanium grades. Thermal expansion is 9 µm/m·K (5 µin/in·°F).
Electrical3
Ti-6Al-5Zr-0.5Mo conducts electricity at 1.1 % IACS, worse than 67% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), worse than 77% of titanium grades.
Sustainability4
Producing a kilogram of Ti-6Al-5Zr-0.5Mo takes about 660 MJ of energy and emits 44 kg of CO₂ — less than 57% of titanium grades. Typical recycled content is 25%.
Manufacturability8
Ti-6Al-5Zr-0.5Mo's machinability is poor (17/100, worse than 89% of titanium grades); weldability good (65/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the titanium family
Yield strength against density for every titanium grade FabDigit runs. Ti-6Al-5Zr-0.5Mo is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Ti-6Al-5Zr-0.5Mo
Is Ti-6Al-5Zr-0.5Mo easy to machine?
Machine like a high-strength titanium alloy: rigid setup, sharp uncoated carbide or PVD-coated tools, low surface speed (20–35 m/min), heavy feed, flood high-pressure coolant, and never dwell — work hardening and fire risk from fine chips.
Can Ti-6Al-5Zr-0.5Mo be welded?
Readily GTAW/plasma/EB welded with full argon or vacuum shielding and matching filler; weld metal is fully transformed beta, so a 600 °C stress relief is normal and hydrogen/oxygen pickup must be avoided.
Can Ti-6Al-5Zr-0.5Mo be formed, bent or molded?
Hot work and form in the 900–1000 °C range with beta forging/final beta heat treatment for creep parts; cold forming is essentially limited to gentle bends with generous radii and springback allowance.
Ti-6Al-5Zr-0.5Mo chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Alalpha stabiliser, main solid-solution strengthener | 5.5 – 6.5 | 6 |
| Zrneutral element, boosts creep strength | 4.5 – 5.5 | 5 |
| Mobeta stabiliser for structure control | 0.4 – 0.6 | 0.5 |
| Sicreep-resistance addition in the IMI 685 version of this composition | 0.2 – 0.3 | 0.25 |
| Feimpurity | ≤ 0.15 | 0.05 |
| Oimpurity; controls strength and ductility | ≤ 0.15 | 0.1 |
| C | ≤ 0.05 | 0.02 |
| N | ≤ 0.04 | 0.01 |
| Hkept low to avoid hydride embrittlement | ≤ 0.01 | 0 |
| Ti | balance |
What surface finishes work on Ti-6Al-5Zr-0.5Mo?
Chemically mill or pickle in HNO₃/HF to remove alpha case after hot work, then anodise, shot peen or apply oxidation/anti-fretting coatings; polishes to a bright grey finish.
Surface treatments FabDigit runs on titanium parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Titanium Ti-6Al-5Zr-0.5Mo in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 3.7155
How much does Ti-6Al-5Zr-0.5Mo cost?
Ti-6Al-5Zr-0.5Mo is a high-cost titanium ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Ti-6Al-5Zr-0.5Mo — frequently asked
What is Ti-6Al-5Zr-0.5Mo used for?
Ti-6Al-5Zr-0.5Mo is typically used for aero-engine casings, high-temperature airframe structure, compressor discs and rings, welded engine ducting and manifolds, beta-forged rotating hardware and hot-section brackets and mounts. In short: creep resistance to 520 °C; weldable near-alpha alloy; beta-processed for creep life.
What is the yield strength of Ti-6Al-5Zr-0.5Mo?
Ti-6Al-5Zr-0.5Mo has a typical yield strength of 900 MPa (131 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 82% of titanium grades. Strength varies by condition: see the 4 listed tempers.
Is Ti-6Al-5Zr-0.5Mo easy to machine?
Not especially — machinability is rated poor (17/100, worse than 89% of titanium grades). Machine like a high-strength titanium alloy: rigid setup, sharp uncoated carbide or PVD-coated tools, low surface speed (20–35 m/min), heavy feed, flood high-pressure coolant, and never dwell — work hardening and fire risk from fine chips.
Can Ti-6Al-5Zr-0.5Mo be welded?
Yes — weldability is rated good (65/100). Readily GTAW/plasma/EB welded with full argon or vacuum shielding and matching filler; weld metal is fully transformed beta, so a 600 °C stress relief is normal and hydrogen/oxygen pickup must be avoided.
What surface finishes work on Ti-6Al-5Zr-0.5Mo?
Chemically mill or pickle in HNO₃/HF to remove alpha case after hot work, then anodise, shot peen or apply oxidation/anti-fretting coatings; polishes to a bright grey finish.
Can Ti-6Al-5Zr-0.5Mo be formed, bent or molded?
Hot work and form in the 900–1000 °C range with beta forging/final beta heat treatment for creep parts; cold forming is essentially limited to gentle bends with generous radii and springback allowance.
What is the maximum service temperature of Ti-6Al-5Zr-0.5Mo?
Ti-6Al-5Zr-0.5Mo is rated for continuous use to about 520°C (968 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Ti-6Al-5Zr-0.5Mo BSTA and Ti-6Al-5Zr-0.5Mo BSTA-AC?
BSTA is the default condition — standard aerospace supply condition: basket-weave transformed-beta structure giving the best creep and fracture toughness at 450–520 °C. BSTA-AC: used for thick discs and forgings where oil quenching is impractical; coarser transformed-beta gives slightly lower strength but the highest toughness and creep resistance. Yield strength is 900 MPa in BSTA versus 860 MPa in BSTA-AC.
How much does Ti-6Al-5Zr-0.5Mo cost?
Ti-6Al-5Zr-0.5Mo is a high-cost titanium ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- IMI 685 (Ti-6Al-5Zr-0.5Mo-0.25Si) high-temperature titanium alloy data — IMI Titanium / Timet (1990)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (titanium alloys) — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- DIN 17851 / Werkstoff-Nr. 3.7155 titanium alloy designations — DIN (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.