html

Alloy713LC and IN738 High-Temperature Superalloys Comparison

High-temperature superalloys are critical materials used in demanding applications such as aerospace, power generation, and industrial gas turbines. Among these, Alloy713LC and IN738 are two widely recognized nickel-based superalloys known for their excellent mechanical properties and resistance to oxidation and creep at elevated temperatures. This article compares their compositions, properties, and typical applications.

Composition and Microstructure

Alloy713LC is a low-carbon variant of Alloy713, designed to improve weldability while maintaining high-temperature strength. Its composition primarily includes nickel (Ni), chromium (Cr), and molybdenum (Mo), with additions of aluminum (Al) and titanium (Ti) for precipitation hardening. The low carbon (LC) content reduces carbide formation, enhancing ductility.

IN738, on the other hand, is a more complex alloy with a higher chromium content for improved oxidation resistance. It also contains cobalt (Co), tantalum (Ta), and tungsten (W), which contribute to its superior creep resistance. The alloy is strengthened by gamma prime (γ’) precipitates, formed by aluminum and titanium.

Mechanical Properties

Both alloys exhibit excellent high-temperature strength, but their performance varies depending on the application:

• Alloy713LC offers good tensile and fatigue strength up to 850°C, making it suitable for turbine blades and vanes in less extreme environments.
• IN738 outperforms Alloy713LC in creep resistance, withstanding temperatures up to 950°C. This makes it ideal for high-stress components like turbine disks and combustion chambers.

Oxidation and Corrosion Resistance

Due to its higher chromium content, IN738 provides superior oxidation and hot corrosion resistance compared to Alloy713LC. This makes IN738 a preferred choice for components exposed to aggressive environments, such as marine or industrial exhaust systems.

Applications

Alloy713LC is commonly used in:

• Gas turbine blades
• Aircraft engine components
• Industrial furnace parts

IN738 is typically employed in more demanding applications, including:

• High-pressure turbine blades
• Power generation turbine components
• Advanced aerospace engines

Conclusion

While both Alloy713LC and IN738 are high-performance superalloys, their suitability depends on specific operational requirements. Alloy713LC is a cost-effective option for moderate-temperature applications, whereas IN738 excels in extreme environments requiring superior creep and oxidation resistance. Engineers must carefully evaluate these properties when selecting materials for high-temperature applications.