UNS N07090: Properties and Applications in High-Temperature Alloys

# UNS N07090: Properties and Applications in High-Temperature Alloys

## Introduction to UNS N07090

UNS N07090 is a nickel-based superalloy known for its exceptional high-temperature strength and corrosion resistance. This alloy belongs to a class of materials specifically designed to withstand extreme environments, making it a critical component in industries such as aerospace, power generation, and chemical processing.

## Chemical Composition

The unique properties of UNS N07090 stem from its carefully balanced chemical composition:

– Nickel (Ni): 58-63% (base element)
– Chromium (Cr): 19-23%
– Cobalt (Co): 13-17%
– Molybdenum (Mo): 4-6%
– Aluminum (Al): 1.4-1.9%
– Titanium (Ti): 2.8-3.3%
– Iron (Fe): ≤1.0%
– Carbon (C): ≤0.08%
– Boron (B): ≤0.008%

## Mechanical Properties

UNS N07090 exhibits remarkable mechanical properties at elevated temperatures:

Property | Value

Tensile Strength (Room Temp) | 1200-1400 MPa
Yield Strength (Room Temp) | 800-950 MPa
Elongation | 15-25%
Creep Resistance (700°C) | Excellent
Fatigue Strength | High

## Key Characteristics

### High-Temperature Stability

The alloy maintains its mechanical integrity at temperatures up to 980°C (1800°F), making it ideal for turbine applications where components are subjected to extreme heat.

### Oxidation Resistance

UNS N07090 forms a protective oxide layer that prevents further oxidation, even in harsh environments containing sulfur and other corrosive elements.

### Creep Resistance

The alloy’s unique microstructure provides exceptional resistance to creep deformation under prolonged stress at high temperatures.

## Heat Treatment

Proper heat treatment is crucial for optimizing the properties of UNS N07090:

– Solution Annealing: Typically performed at 1080-1120°C (1975-2050°F) followed by rapid cooling
– Aging: Often conducted at 700-800°C (1290-1470°F) for 8-16 hours to precipitate strengthening phases

## Applications

UNS N07090 finds use in several demanding applications:

### Aerospace Industry

– Turbine blades and vanes
– Combustion chambers
– Afterburner components

### Power Generation

– Gas turbine components
– Nuclear reactor parts
– Heat exchangers

### Industrial Processing

– Chemical processing equipment
– Furnace components
– High-temperature fasteners

## Fabrication Considerations

Working with UNS N07090 requires special attention:

– Machining: Requires rigid setups and sharp tools due to work hardening tendencies
– Welding: Best performed using matching filler metals and proper pre/post-weld heat treatment
– Forming: Hot forming is preferred for complex shapes to reduce springback

## Comparison with Other Superalloys

While similar to alloys like Inconel 718 and Waspaloy, UNS N07090 offers:

– Higher temperature capability than Inconel 718
– Better creep resistance than many cobalt-based alloys
– Superior oxidation resistance compared to many nickel-based alternatives

## Conclusion

UNS N07090 represents a high-performance solution for extreme temperature applications where conventional materials would fail. Its combination of strength, corrosion resistance, and thermal stability makes it indispensable in critical engineering applications. As technology advances and operating temperatures continue to rise in various industries, the demand for specialized alloys like UNS N07090 is expected to grow significantly.