LAS/SiC LAS-UD
Reinforced grade
also Blackglas
LAS-UD = unidirectional SiC fiber / LAS glass-ceramic
Choose when load path is one-dimensional (struts, booms, tensile test coupons) and maximum axial strength/toughness is needed.
Values for the LAS-UD condition
Other LAS/SiC grades and fills
LAS/SiC is listed in 8 conditions; see the grade overview at LAS/SiC.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
SiC whisker / particulate reinforced LAS glass-ceramic | Discontinuous reinforcement for near-net-shape, isotropic parts where cost matters more than toughness. | — | 150 | 0.15 | — |
polymer-derived SiOC (black glass) matrix with SiC or C fiber | Resin-transfer/prepreg route via siloxane precursor pyrolysis — pick it for large, complex, low-cost CMC shells rather than peak properties. | — | 250 | 0.5 | — |
LAS-2DDefault 2D woven SiC (Nicalon) fiber / lithium aluminosilicate matrix | General-purpose plate/panel lay-up: balanced in-plane properties for structural CMC panels and heat-shield hardware. | — | 260 | 0.7 | — |
calcium aluminosilicate matrix with SiC fiber | Higher-temperature, lithium-free matrix; better creep and steam resistance than LAS at 1000–1100 °C. | — | 300 | 0.8 | — |
barium magnesium aluminosilicate matrix with SiC fiber | Top-end glass-ceramic matrix for the hottest service (up to ~1200 °C) and best oxidation stability of this family. | — | 320 | 0.7 | — |
borosilicate glass matrix with SiC fiber | Lowest-cost, lowest-temperature member: easy hot-press consolidation, high room-temperature strength, but softens above ~600 °C. | — | 500 | 0.9 | — |
Carbon fiber reinforced glass-ceramic matrix | Highest stiffness and truly near-zero CTE for space optics/benches, but only usable in vacuum or inert atmosphere above ~450 °C. | — | 600 | 0.6 | — |
LAS-UDThis page Unidirectional SiC fiber / LAS glass-ceramic | Choose when load path is one-dimensional (struts, booms, tensile test coupons) and maximum axial strength/toughness is needed. | — | 700 | 0.9 | — |
What is LAS/SiC LAS-UD?
LAS/SiC LAS-UD is LAS/SiC in the LAS-UD grade — choose when load path is one-dimensional (struts, booms, tensile test coupons) and maximum axial strength/toughness is needed. LAS/SiC LAS-UD has a tensile strength of 700 MPa (102 ksi), stronger than 72% of composite grades. Elongation at break is 0.9% and the elastic modulus is 135 GPa (19.6 Msi). LAS/SiC LAS-UD has a density of 2.5 g/cm³ (0.0903 lb/in³), heavier than 81% of composite grades. LAS-2D is the default condition FabDigit quotes; LAS-UD is available on request or by drawing note.
Advantages
- High service temperature — 1,000°C (1,832 °F), better than 91% of composite grades
- Good UV / weathering resistance — 98/100, better than 85% of composite grades
- Tough — resists crack growth — 20 MPa·√m (18.2 ksi·√in), better than 76% of composite grades
Limitations
- Difficult to machine — 7/100, worse than 96% of composite grades
- Heavy — 2.5 g/cm³ (0.0903 lb/in³), worse than 81% of composite grades
- Limited ductility — 0.9%, worse than 80% of composite grades
LAS/SiC LAS-UD properties
Typical room-temperature values for LAS/SiC LAS-UD; 14 are specific to this condition. Other listed values are LAS/SiC reference data and may not represent this condition. Bars are the position among composite grades.
Physical2
LAS/SiC LAS-UD has a density of 2.5 g/cm³ (0.0903 lb/in³), heavier than 81% of composite grades.
Mechanical12
LAS/SiC LAS-UD has a tensile strength of 700 MPa (102 ksi), stronger than 72% of composite grades. Elongation at break is 0.9% and the elastic modulus is 135 GPa (19.6 Msi).
Thermal7
LAS/SiC LAS-UD is rated for continuous service to 1,000°C (1,832 °F). It conducts heat at 3 W/m·K (1.73 BTU/hr·ft·°F), better than 63% of composite grades. Thermal expansion is 2 µm/m·K (1.11 µin/in·°F).
Electrical1
LAS/SiC LAS-UD has an electrical resistivity of 0.5 Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (78/100), worse than 52% of composite grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of LAS/SiC LAS-UD takes about 320 MJ of energy and emits 26 kg of CO₂ — more than 72% of composite grades. Typical recycled content is 0%.
Manufacturability2
LAS/SiC LAS-UD's machinability is not recommended (7/100, 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 LAS/SiC LAS-UD
Is LAS/SiC easy to machine?
Diamond grinding, ultrasonic or waterjet/laser cutting only; avoid drilling near edges to prevent delamination and fiber pull-out.
Can LAS/SiC be welded?
Not weldable — join by brazing with active (Ti-containing) filler, glass sealing or mechanical/pinned attachments.
Can LAS/SiC be formed, bent or molded?
Fiber tow slurry impregnation into prepreg, lay-up, then hot pressing in the glassy state (~1200–1400 °C) followed by a ceramming/crystallisation hold; Blackglas variants use RTM/prepreg plus repeated polymer pyrolysis cycles.
What surface finishes work on LAS/SiC?
Seal coat with CVD SiC or a glass overlay for oxidation protection; surfaces can be lapped but fiber texture limits optical polish.
LAS/SiC 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 (Nicalon / Hi-Nicalon)vol % continuous fiber, with C or BN interphase ~0.1–1 µm | 30 – 50 | 40 |
| SiO2matrix oxide basis | 55 – 72 | 65 |
| Al2O3matrix oxide basis | 15 – 27 | 21 |
| Li2Oβ-spodumene/β-quartz former, gives near-zero CTE | 3 – 6 | 4.5 |
| MgO | 0 – 2 | 1 |
| ZnO | 0 – 2 | 1 |
| TiO2 + ZrO2nucleating agents for crystallisation | 2 – 6 | 4 |
| Nb2O5 / Ta2O5added in Corning-type LAS-III to improve fiber/matrix stability | 0 – 4 | 2 |
LAS/SiC LAS-UD — frequently asked
What is LAS/SiC LAS-UD used for?
LAS/SiC LAS-UD is typically used for radomes, missile structural components, heat exchanger parts and aerospace secondary structures. In short: low-temperature-processed CMC; radome-grade glass ceramic; 900 °C service ceiling.
What is the tensile strength of LAS/SiC LAS-UD?
LAS/SiC LAS-UD has a typical tensile strength of 700 MPa (102 ksi) — stronger than 72% of composite grades. Strength varies by condition: see the 8 listed tempers.
Is LAS/SiC LAS-UD easy to machine?
Not especially — machinability is rated not recommended (7/100, worse than 96% of composite grades). Diamond grinding, ultrasonic or waterjet/laser cutting only; avoid drilling near edges to prevent delamination and fiber pull-out.
Can LAS/SiC LAS-UD be welded?
Not weldable — join by brazing with active (Ti-containing) filler, glass sealing or mechanical/pinned attachments.
What surface finishes work on LAS/SiC LAS-UD?
Seal coat with CVD SiC or a glass overlay for oxidation protection; surfaces can be lapped but fiber texture limits optical polish.
Can LAS/SiC LAS-UD be formed, bent or molded?
Fiber tow slurry impregnation into prepreg, lay-up, then hot pressing in the glassy state (~1200–1400 °C) followed by a ceramming/crystallisation hold; Blackglas variants use RTM/prepreg plus repeated polymer pyrolysis cycles.
What is the maximum service temperature of LAS/SiC LAS-UD?
LAS/SiC LAS-UD is rated for continuous use to about 1,000°C (1,832 °F), and briefly to 1,200°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Engineered Materials Handbook Vol. 4: Ceramics and Glasses (CMC section) — ASM International (1991)
- Ceramic Matrix Composites: Fiber Reinforced Ceramics and their Applications — Wiley-VCH (2008)
- Compglas SiC fiber reinforced glass-ceramic composite data — Corning Incorporated (1990)
- Blackglas ceramic composite (SiOC matrix) technical bulletin — AlliedSignal / Northrop Grumman (1998)
- NIST/NASA structural ceramics and CMC property compilations — NASA Glenn Research Center (2005)
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.