GTD-111 superalloy patent dispute

Another externality, and this one has to do with intellectual property. It has to do with large turbine blades. These are land-based turbines. I'll pass around — this one comes from either a 757 or 747 engine from about twenty, twenty-five years ago, maybe even older. You can take it apart. It's a single crystal turbine blade. It's been cut by wire electrical discharge machining so you can see the inside structure, and they cool these things with the compressor air from the engine. The cooling air is about 500° Fahrenheit because that's the temperature when you squeeze the air in the engine to thirty atmospheres pressure so you can burn it.

GE developed GTD-111 in early 1980s but couldn't patent the composition (too overlapped); patent office denied the heat-treatment patent for 18 years, then granted it after competitors had adopted the alloy. Royalty windfall. Chromalloy rejuvenation work on GTD-111 blades via HIP ties the case to §4.

There's a story here. There was a General Electric alloy called GTD-111, and it had this very blocky, squarish gamma prime precipitate. The composition was overlapped by lots of other alloys, so when General Electric developed it in the early 1980s they couldn't get a patent on the composition. They did apply for a patent on the heat treatment, and the Patent Office kept denying it.