# NIMONIC Alloy 90 UNS N07090: Properties and Applications
## Introduction
NIMONIC Alloy 90 (UNS N07090) is a high-performance nickel-chromium-cobalt alloy that has gained significant recognition in various industries due to its exceptional mechanical properties and resistance to high temperatures. Developed by Rolls-Royce in the 1940s, this superalloy has become a cornerstone material for applications requiring strength and durability in extreme environments.
## Chemical Composition
The chemical composition of NIMONIC Alloy 90 plays a crucial role in its performance characteristics:
– Nickel (Ni): 55-60%
– Chromium (Cr): 18-21%
– Cobalt (Co): 15-21%
– Titanium (Ti): 2.0-3.0%
– Aluminum (Al): 1.0-2.0%
– Iron (Fe): ≤2.0%
– Carbon (C): ≤0.13%
– Manganese (Mn): ≤1.0%
– Silicon (Si): ≤1.0%
– Copper (Cu): ≤0.5%
– Boron (B): ≤0.01%
– Zirconium (Zr): ≤0.15%
## Mechanical Properties
NIMONIC Alloy 90 exhibits impressive mechanical properties that make it suitable for demanding applications:
– Tensile Strength: 1200-1400 MPa (at room temperature)
– Yield Strength: 800-1000 MPa (at room temperature)
– Elongation: 15-25%
– Hardness: 30-40 HRC
– Creep Resistance: Excellent at temperatures up to 815°C (1500°F)
– Fatigue Strength: Outstanding under cyclic loading conditions
## Physical Properties
The physical characteristics of NIMONIC Alloy 90 include:
– Density: 8.19 g/cm³
– Melting Range: 1290-1350°C (2350-2460°F)
– Thermal Conductivity: 11.2 W/m·K (at 20°C)
– Electrical Resistivity: 1.25 μΩ·m (at 20°C)
– Coefficient of Thermal Expansion: 13.5 μm/m·K (20-100°C)
## Heat Treatment
NIMONIC Alloy 90 typically undergoes the following heat treatment process:
– Solution Treatment: 1080-1120°C (1975-2050°F) followed by rapid cooling
– Aging Treatment: 700-750°C (1290-1380°F) for 16 hours, air cooled
This heat treatment sequence optimizes the alloy’s mechanical properties by promoting the formation of gamma prime (γ’) precipitates, which significantly enhance its strength at elevated temperatures.
## Corrosion Resistance
NIMONIC Alloy 90 demonstrates excellent corrosion resistance in various environments:
– Oxidation resistance up to 980°C (1800°F)
– Good resistance to carburizing and nitriding atmospheres
– Moderate resistance to sulfur-containing environments
– Excellent resistance to chloride-ion stress-corrosion cracking
## Applications
Due to its exceptional properties, NIMONIC Alloy 90 finds applications in several critical industries:
### Aerospace Industry
– Turbine blades and discs
– Combustion chamber components
– Exhaust systems
– Afterburner parts
### Power Generation
– Gas turbine components
– Steam turbine blades
– High-temperature fasteners
– Valve components
### Industrial Applications
– Hot working tools and dies
– Fasteners for high-temperature service
– Nuclear reactor components
– Chemical processing equipment
## Fabrication and Machining
Working with NIMONIC Alloy 90 requires special considerations:
Keyword: NIMONIC Alloy 90 UNS N07090
– Machining: Requires rigid machine tools, positive rake angles, and slow speeds
– Wel