How was Inconel 718 created?

In the 1950s, there was an anticipated demand for a material for steam lines in power plants that could carry steam at supercritical pressures. Goals for product characteristics amounted to ease of weldability, workable into tubing, creep resistance, and non age-hardening material. From prior work with single alloys using commonly alloyed materials like titanium and chromium, researchers knew an advanced combination of elements would be needed to form an alloy matrix with the necessary properties.

The research that led to the creation and patenting of Inconel 718 stemmed from research to develop 625. The failure of samples after a simple age hardening test spurred the creation of 718 - a superalloy with high strength, good weldability, and the ability to be fabricated in a variety of shapes and forms.

What were the first applications of this superalloy?

Initial processing of Inconel 718 was difficult compared to today, with vacuum processing an early and unrefined technology. This lead to a product that was not nearly as uniform as modern production, but the unique properties of this alloy made it very desirable, as it could replace complex welded assemblies with castings, while remaining highly weldable. 

How is Inconel 718 used today?

This grade of Inconel accounts for roughly half of the production of superalloys today, and is widely used in power industries due to its high stress resistance at temperatures found in gas turbines. It is so prevalent in these applications that around 30% of the weight of a typical engine comes from alloy 718. It is used in compressor blades and vanes, shafts, supports cases and more.

Almost half of the Inconel 718 produced today is used in aerospace applications like aircraft and rocket engines, for many essential components like blades and sheets. This super alloy excels at a range of temperatures while maintaining creep resistance, corrosion resistance, tensile strength, and yield strength that prevents stress fractures in common operating conditions. The strong toughness at low temperatures that makes it ideal for spacecraft also make it perfect for cryogenic applications, such as storage containers for liquid nitrogen held at -196 degrees .