SCS-6/Ti-6Al-4V UD-25
Reinforced grade
UD-25 = unidirectional, ~25 vol% SCS-6
Use the common mid-fibre-content plate when longitudinal stiffness (185 GPa) and transverse properties must be traded off, giving 1480 MPa tensile strength at 4.07 g/cm³.
Values for the UD-25 condition
Other SCS-6/Ti-6Al-4V grades and fills
SCS-6/Ti-6Al-4V is listed in 4 conditions; see the grade overview at SCS-6/Ti-6Al-4V.
Compare all 4 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Unidirectional, ~15 vol% SCS-6 | Choose this low-cost transitional TMC when ~15 vol% fibre suffices: better transverse behaviour and damage tolerance, but only 156 GPa modulus and 1200 MPa longitudinal strength. | 950 | 1,200 | 0.9 | — |
UD-25This page Unidirectional, ~25 vol% SCS-6 | Use the common mid-fibre-content plate when longitudinal stiffness (185 GPa) and transverse properties must be traded off, giving 1480 MPa tensile strength at 4.07 g/cm³. | 1,050 | 1,480 | 0.85 | — |
UD-35Default Unidirectional, ~35 vol% SCS-6, HIP consolidated | Pick as the baseline for aero-engine blings and struts: HIP-consolidated ~35 vol% unidirectional fibre gives the best balance of longitudinal stiffness (205 GPa) and 1750 MPa strength. | 1,100 | 1,750 | 0.85 | — |
Unidirectional, ~40 vol% SCS-6 | Pick for the highest longitudinal specific stiffness and strength (225 GPa, 1900 MPa) in bling inner rings; at the ~40 vol% packing limit transverse properties and consolidation risk are worst. | 1,150 | 1,900 | 0.8 | — |
What is SCS-6/Ti-6Al-4V UD-25?
SCS-6/Ti-6Al-4V UD-25 is SCS-6/Ti-6Al-4V in the UD-25 grade — use the common mid-fibre-content plate when longitudinal stiffness (185 GPa) and transverse properties must be traded off, giving 1480 MPa tensile strength at 4.07 g/cm³. SCS-6/Ti-6Al-4V UD-25 has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,480 MPa (215 ksi) — stronger than 100% of composite grades. Elongation at break is 0.85% and the elastic modulus is 185 GPa (26.8 Msi). SCS-6/Ti-6Al-4V UD-25 has a density of 4.07 g/cm³ (0.147 lb/in³), heavier than 94% of composite grades. UD-35 is the default condition FabDigit quotes; UD-25 is available on request or by drawing note.
Advantages
- High strength — 1,050 MPa (152 ksi), better than 100% of composite grades
- Tough — resists crack growth — 45 MPa·√m (41 ksi·√in), better than 100% of composite grades
- Good UV / weathering resistance — 100/100, better than 93% of composite grades
- High service temperature — 500°C (932 °F), better than 87% of composite grades
- Stiff — 185 GPa (26.8 Msi), better than 77% of composite grades
Limitations
- High embodied carbon — 80 kg CO₂/kg, worse than 98% of composite grades
- Difficult to machine — 6/100, worse than 96% of composite grades
- Heavy — 4.07 g/cm³ (0.147 lb/in³), worse than 94% of composite grades
- Limited ductility — 0.85%, worse than 81% of composite grades
SCS-6/Ti-6Al-4V UD-25 properties
Typical room-temperature values for SCS-6/Ti-6Al-4V UD-25; 16 are specific to this condition. Other listed values are SCS-6/Ti-6Al-4V reference data and may not represent this condition. Bars are the position among composite grades.
Physical1
SCS-6/Ti-6Al-4V UD-25 has a density of 4.07 g/cm³ (0.147 lb/in³), heavier than 94% of composite grades.
Mechanical12
SCS-6/Ti-6Al-4V UD-25 has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,480 MPa (215 ksi) — stronger than 100% of composite grades. Elongation at break is 0.85% and the elastic modulus is 185 GPa (26.8 Msi).
Thermal6
SCS-6/Ti-6Al-4V UD-25 is rated for continuous service to 500°C (932 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), better than 74% of composite grades. Thermal expansion is 7.2 µm/m·K (4 µin/in·°F).
Electrical1
SCS-6/Ti-6Al-4V UD-25 has an electrical resistivity of 1.45×10⁻⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 64% of composite grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of SCS-6/Ti-6Al-4V UD-25 takes about 1,300 MJ of energy and emits 80 kg of CO₂ — more than 98% of composite grades. Typical recycled content is 0%.
Manufacturability2
SCS-6/Ti-6Al-4V UD-25's machinability is not recommended (6/100, worse than 96% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SCS-6/Ti-6Al-4V UD-25
Is SCS-6/Ti-6Al-4V easy to machine?
No conventional turning or milling: the SiC monofilament is around 2500 HV, so use diamond wheel grinding, wire EDM or abrasive waterjet. Trimmed edges must be controlled to prevent fiber pull-out and delamination.
Can SCS-6/Ti-6Al-4V be welded?
Cannot be fusion welded; the weld pool destroys the fibers and forms a brittle reaction layer. Use diffusion bonding, brazing, or hybrid joints in which titanium end fittings are mechanically fastened or co-consolidated by HIP.
Can SCS-6/Ti-6Al-4V be formed, bent or molded?
Consolidated to near-net shape from foil-fiber-foil stacks or plasma-sprayed monotape windings by hot isostatic pressing at roughly 900–925 °C, 100–170 MPa for 1–2 h. Essentially no plastic forming after consolidation.
What surface finishes work on SCS-6/Ti-6Al-4V?
Surfaces can be anodized or coated with thermal barrier and oxidation-resistant systems. Cut edges should be sealed or coated so exposed fiber ends do not admit corrosion or oxidation.
SCS-6/Ti-6Al-4V 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 |
|---|---|---|
| SiC fiber (SCS-6 monofilament, 140 µm, C≈35 vol% nominal; wt% varies with fiber volume fraction | 12 – 33 | 26.7 |
| Almatrix per AMS 4911 / ASTM B265 Gr.5; nominal shown as composite wt% | 5.5 – 6.75 | 4.4 |
| Vmatrix Ti-6Al-4V | 3.5 – 4.5 | 2.9 |
| Fematrix max | ≤ 0.3 | 0.1 |
| Omatrix max | ≤ 0.2 | 0.13 |
| Cmatrix max (excludes fiber carbon core/coating) | ≤ 0.08 | — |
| Nmatrix max | ≤ 0.05 | — |
| Hmatrix max | ≤ 0.02 | — |
| Timatrix balance | balance | — |
SCS-6/Ti-6Al-4V UD-25 — frequently asked
What is SCS-6/Ti-6Al-4V UD-25 used for?
SCS-6/Ti-6Al-4V UD-25 is typically used for jet engine rings, compressor blisks and high-temperature aerospace shafts. In short: highest-strength titanium composite; 500 °C service capability; grinding and EDM only.
What is the yield strength of SCS-6/Ti-6Al-4V UD-25?
SCS-6/Ti-6Al-4V UD-25 has a typical yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,480 MPa (215 ksi) — stronger than 100% of composite grades. Strength varies by condition: see the 4 listed tempers.
Is SCS-6/Ti-6Al-4V UD-25 easy to machine?
Not especially — machinability is rated not recommended (6/100, worse than 96% of composite grades). No conventional turning or milling: the SiC monofilament is around 2500 HV, so use diamond wheel grinding, wire EDM or abrasive waterjet. Trimmed edges must be controlled to prevent fiber pull-out and delamination.
Can SCS-6/Ti-6Al-4V UD-25 be welded?
Cannot be fusion welded; the weld pool destroys the fibers and forms a brittle reaction layer. Use diffusion bonding, brazing, or hybrid joints in which titanium end fittings are mechanically fastened or co-consolidated by HIP.
What surface finishes work on SCS-6/Ti-6Al-4V UD-25?
Surfaces can be anodized or coated with thermal barrier and oxidation-resistant systems. Cut edges should be sealed or coated so exposed fiber ends do not admit corrosion or oxidation.
Can SCS-6/Ti-6Al-4V UD-25 be formed, bent or molded?
Consolidated to near-net shape from foil-fiber-foil stacks or plasma-sprayed monotape windings by hot isostatic pressing at roughly 900–925 °C, 100–170 MPa for 1–2 h. Essentially no plastic forming after consolidation.
What is the maximum service temperature of SCS-6/Ti-6Al-4V UD-25?
SCS-6/Ti-6Al-4V UD-25 is rated for continuous use to about 500°C (932 °F), and briefly to 700°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SCS-6/Ti-6Al-4V UD-35 and SCS-6/Ti-6Al-4V UD-15?
UD-35 is the default condition — pick as the baseline for aero-engine blings and struts: HIP-consolidated ~35 vol% unidirectional fibre gives the best balance of longitudinal stiffness (205 GPa) and 1750 MPa strength. UD-15: choose this low-cost transitional TMC when ~15 vol% fibre suffices: better transverse behaviour and damage tolerance, but only 156 GPa modulus and 1200 MPa longitudinal strength. Yield strength is 1,100 MPa in UD-35 versus 950 MPa in UD-15.
Sources
- ASM Handbook Vol.21: Composites — Titanium Matrix Composites — ASM International (2001)
- MIL-HDBK-17 (CMH-17) Vol.4: Metal Matrix Composites — US DoD (2002)
- SCS-6 Silicon Carbide Monofilament Datasheet — Specialty Materials Inc. (2020)
- AMS 4911 / ASTM B265 Grade 5 (Ti-6Al-4V matrix chemistry) — SAE / ASTM (2020)
- NASA Glenn TMC property reports (SCS-6/Ti-6-4 panel test data) — NASA (1996)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.