Udimet 720: High-Strength Nickel Superalloy for Turbine Disc Applications
· Published: 2026-08-10 · Updated: August 2026
Udimet 720 is a high-strength, corrosion-resistant nickel-based superalloy developed specifically for turbine disc applications in modern gas turbine engines. Its composition includes 16% chromium, 14.7% cobalt, 3% molybdenum, 4.7% titanium, 2.5%...
Udimet 720 is a high-strength, corrosion-resistant nickel-based superalloy developed specifically for turbine disc applications in modern gas turbine engines. Its composition includes 16% chromium, 14.7% cobalt, 3% molybdenum, 4.7% titanium, 2.5% aluminum, and 1.3% tungsten. Udimet 720 achieves its exceptional strength through high gamma-prime volume fraction (approximately 45-50%) and optimized heat treatment including solution treatment above the gamma-prime solvus followed by controlled cooling and aging. The alloy exhibits excellent fatigue strength, creep resistance, and dwell fatigue crack growth resistance at intermediate temperatures (650-760°C), making it the material of choice for advanced turbine discs in high-pressure compressor and turbine stages.
Quick Facts
| Category | |
| Standard | |
| Density | 8.08 g/cm³ |
| Yield Strength | |
| Tensile Strength |
Global Equivalents & Cross-Reference
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Frequently Asked Questions
What makes Udimet 720 different from Inconel 718?
Udimet 720 has a higher gamma-prime volume fraction (45-50% vs 15-20%) and higher service temperature capability (760°C vs 700°C) than Inconel 718. Udimet 720 is specifically designed for turbine disc applications where dwell fatigue crack growth resistance is critical.
Is Udimet 720 weldable?
Udimet 720 has limited weldability due to its high gamma-prime content and susceptibility to strain-age cracking and microfissuring. It is typically joined by inertia welding or diffusion bonding rather than conventional fusion welding.
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu
Specialty Metals — Engineering Reference
Non-ferrous metals — aluminum, copper, titanium, zinc, magnesium — serve applications where steel cannot: electrical conductivity, thermal management, weight reduction, corrosion resistance in specific chemical environments. Each metal family has its own classification system and selection logic.
ASTM B209/B221 (Al), ASTM B152/B187 (Cu), ASTM B265/B348 (Ti), ASTM B86 (Zn), ASTM B90/B91 (Mg)
Electrical wiring and busbars (Cu), aircraft structures and automotive bodies (Al), medical implants and aerospace fasteners (Ti), die-cast consumer products (Zn), lightweight electronic enclosures (Mg)
Galvanic corrosion is the #1 failure mode in multi-metal assemblies. When joining dissimilar metals, consult the galvanic series: the more anodic metal will corrode preferentially. Use isolating washers, protective coatings, or select metals close together on the galvanic series.