Nickel Alloy CMSX-4
CMSX-4 is a second-generation single-crystal nickel-base superalloy containing rhenium, directionally solidified without grain boundaries for maximum creep-rupture strength in the hottest turbine sections.
Reference datasheet — CMSX-4 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 FHT condition
CMSX-4 tempers and conditions
CMSX-4 is supplied in 4 conditions, soft to hard. FHT 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 |
|---|---|---|---|---|---|---|
Spheroidize annealed | Pick only for process-development, orientation checks or castings that will be solutioned later; dendritic segregation and coarse eutectic γ′ limit properties. | 830 | 950 | 8 | 38 HRC | 1.3 % IACS |
Solution heat treated | Intermediate condition: γ′ eutectic fully dissolved and dendrites homogenised, supplied when the customer performs its own coating diffusion + ageing cycle. | 870 | 1,030 | 15 | 39 HRC | 1.3 % IACS |
FHTDefault Fully heat treated: solution 1277–1321 °C + 1140 °C/4 h + 871 °C/20 h,… | Standard flight-hardware condition: uniform cuboidal γ′ ≈0.45 µm giving peak creep-rupture life at 950–1100 °C. | 920 | 1,100 | 12 | 41 HRC | — |
hot isostatic pressing (≈1290 °C / 100–170 MPa) followed by full heat treatment | Choose when casting micro-porosity must be closed for maximum LCF/HCF life and creep scatter reduction in critical blades. | 930 | 1,140 | 16 | 42 HRC | 1.3 % IACS |
Supply forms, finishes and certifications
Ways CMSX-4 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FHT-COAT | FHT + coating | Surface finish |
What is CMSX-4?
CMSX-4 is a second-generation single-crystal nickel-base superalloy containing rhenium, directionally solidified without grain boundaries for maximum creep-rupture strength in the hottest turbine sections. It is specified for high-pressure blades and vanes to about 1100 °C, with 920 MPa yield, 1100 MPa tensile, 12 % elongation and 41 HRC after full heat treatment. Bare oxidation and hot-corrosion resistance is only moderate (score 50), so parts run with aluminide or MCrAlY coatings and often a thermal barrier. It is cast-only and non-weldable in load-bearing sections; rhenium content and single-crystal casting yield make it costly, with DS CM 247 LC the common lower-cost alternative. CMSX-4 has a density of 8.7 g/cm³ (0.314 lb/in³), heavier than 75% of nickel alloy grades. It melts at 1,320°C (2,408 °F). CMSX-4 has a yield strength of 920 MPa (133 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 94% of nickel alloy grades. Elongation at break is 12% and the elastic modulus is 128 GPa (18.6 Msi).
What is CMSX-4 used for?
- single-crystal turbine blades
- high-pressure turbine vanes
- advanced jet engine hot-section parts
Advantages
- High strength — 920 MPa (133 ksi), better than 94% of nickel alloy grades
- High service temperature — 1,100°C (2,012 °F), better than 88% of nickel alloy grades
Limitations
- Poor heat conductor — 7.7 W/m·K (4.45 BTU/hr·ft·°F), worse than 100% of nickel alloy grades
- Low stiffness — 128 GPa (18.6 Msi), worse than 99% of nickel alloy grades
- High embodied carbon — 22 kg CO₂/kg, worse than 99% of nickel alloy grades
- Limited formability — 3/100, worse than 97% of nickel alloy grades
- Difficult to machine — 8/100, worse than 96% of nickel alloy grades
CMSX-4 properties
Typical room-temperature values for CMSX-4-FHT; bars are the position among nickel alloy grades.
Physical3
CMSX-4 has a density of 8.7 g/cm³ (0.314 lb/in³), heavier than 75% of nickel alloy grades. It melts at 1,320°C (2,408 °F).
Mechanical14
CMSX-4 has a yield strength of 920 MPa (133 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 94% of nickel alloy grades. Elongation at break is 12% and the elastic modulus is 128 GPa (18.6 Msi).
Thermal6
CMSX-4 is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 7.7 W/m·K (4.45 BTU/hr·ft·°F), worse than 100% of nickel alloy grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
CMSX-4 conducts electricity at 1.3 % IACS, worse than 89% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 93% of nickel alloy grades.
Sustainability4
Producing a kilogram of CMSX-4 takes about 300 MJ of energy and emits 22 kg of CO₂ — more than 99% of nickel alloy grades. Typical recycled content is 15%.
Manufacturability8
CMSX-4's machinability is not recommended (8/100, worse than 96% of nickel alloy grades); weldability not recommended (10/100); formability not recommended (3/100).
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 nickel alloy family
Yield strength against density for every nickel alloy grade FabDigit runs. CMSX-4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CMSX-4
Is CMSX-4 easy to machine?
Effectively grind/EDM/ECM territory — creep-feed grinding for platforms and shrouds, EDM/ECM or laser for cooling holes; conventional carbide turning gives very low tool life and risks recrystallisation of the strain-hardened surface.
Can CMSX-4 be welded?
Fusion welding is avoided on load-bearing sections (liquation and strain-age cracking, loss of single-crystal epitaxy); repairs use tightly controlled epitaxial laser metal deposition, TLP/diffusion brazing with Ni-Hf-B or Ni-Pd fillers, followed by full re-solution and ageing.
Can CMSX-4 be formed, bent or molded?
Cast-only: Bridgman withdrawal directional solidification with a seed or spiral grain selector, tight thermal gradient control to avoid freckles, stray grains and high-angle boundaries; ceramic-core investment shells for internal cooling passages.
CMSX-4 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 |
|---|---|---|
| Cr | 6.2 – 6.8 | 6.5 |
| Co | 9 – 10 | 9.6 |
| Mo | 0.4 – 0.8 | 0.6 |
| W | 6 – 6.8 | 6.4 |
| Ta | 6.2 – 6.8 | 6.5 |
| Resecond-generation SX alloy addition; raises creep strength | 2.8 – 3.2 | 3 |
| Alγ′ former | 5.4 – 5.8 | 5.6 |
| Ti | 0.8 – 1.2 | 1 |
| Hfimproves coating adherence | 0.05 – 0.15 | 0.1 |
| Ckept very low; no grain boundaries to strengthen | ≤ 0.01 | 0 |
| Btrace | ≤ 0.01 | |
| Zrtrace | ≤ 0.01 | |
| Slow-sulphur melting for oxidation life | ≤ 5×10⁻⁴ | |
| Nibalance, approx. 61.7% | balance |
What surface finishes work on CMSX-4?
Grit blast + chemical/thermal core removal, then pack or CVD aluminide, Pt-aluminide or MCrAlY bond coat and EB-PVD/APS YSZ thermal barrier; no anodizing, and any surface work must stay below recrystallisation-inducing strain levels.
Surface treatments FabDigit runs on nickel alloy 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).
Plating
Thermal Spray
How much does CMSX-4 cost?
CMSX-4 is a high-cost nickel alloy ($$$$), 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.
CMSX-4 — frequently asked
What is CMSX-4 used for?
CMSX-4 is typically used for single-crystal turbine blades, high-pressure turbine vanes and advanced jet engine hot-section parts. In short: highest creep-rupture strength; single-crystal, rhenium-bearing; grind and EDM only.
What is the yield strength of CMSX-4?
CMSX-4 has a typical yield strength of 920 MPa (133 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 94% of nickel alloy grades. Strength varies by condition: see the 4 listed tempers.
Is CMSX-4 easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 96% of nickel alloy grades). Effectively grind/EDM/ECM territory — creep-feed grinding for platforms and shrouds, EDM/ECM or laser for cooling holes; conventional carbide turning gives very low tool life and risks recrystallisation of the strain-hardened surface.
Can CMSX-4 be welded?
Not readily — weldability is rated not recommended (10/100). Fusion welding is avoided on load-bearing sections (liquation and strain-age cracking, loss of single-crystal epitaxy); repairs use tightly controlled epitaxial laser metal deposition, TLP/diffusion brazing with Ni-Hf-B or Ni-Pd fillers, followed by full re-solution and ageing.
What surface finishes work on CMSX-4?
Grit blast + chemical/thermal core removal, then pack or CVD aluminide, Pt-aluminide or MCrAlY bond coat and EB-PVD/APS YSZ thermal barrier; no anodizing, and any surface work must stay below recrystallisation-inducing strain levels.
Can CMSX-4 be formed, bent or molded?
Cast-only: Bridgman withdrawal directional solidification with a seed or spiral grain selector, tight thermal gradient control to avoid freckles, stray grains and high-angle boundaries; ceramic-core investment shells for internal cooling passages.
What is the maximum service temperature of CMSX-4?
CMSX-4 is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CMSX-4-FHT and CMSX-4-AC?
FHT is the default condition — standard flight-hardware condition: uniform cuboidal γ′ ≈0.45 µm giving peak creep-rupture life at 950–1100 °C. AC: pick only for process-development, orientation checks or castings that will be solutioned later; dendritic segregation and coarse eutectic γ′ limit properties. Yield strength is 920 MPa in FHT versus 830 MPa in AC.
How much does CMSX-4 cost?
CMSX-4 is a high-cost nickel alloy ($$$$), 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
- CMSX-4 Alloy Data Sheet (single-crystal superalloy) — Cannon-Muskegon Corporation (2020)
- Superalloys 1996 — 'Development of the Rhenium-containing Superalloys CMSX-4 and CM 186 LC' — TMS (1996)
- ASM Handbook Vol. 1: Properties and Selection — Superalloys — ASM International (1990)
- Superalloys: A Technical Guide, 2nd ed. — ASM International (2002)
- Thermophysical and mechanical property compilations for single-crystal Ni-base superalloys — open literature / NIST-type compilations (2018)
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.