Pratt & Whitney TLP bonding patent (1972) and Owczarski paper (1974)

Origin case for transient liquid phase diffusion bonding as practiced in the superalloy industry. Patent 1972, paper 1973 conference / April 1974 *Welding Journal*. Authors: Scott Duvall, Bill Owczarski, Dia Polonis. Uses nickel-boron interlayer (eutectic at ~1035°C vs 1455°C pure nickel) on nickel-based superalloys.

In TLP, we're going to introduce a liquid in between, so you don't have to have all this heavy pressure to break down the asperity peaks. If you interpose a liquid, you may have a thicker joint, but if you're smart about what liquid you interpose, you can introduce a brazing alloy in between. On nickel-based superalloys, you can use nickel-boron interlayers, which is exactly what Pratt & Whitney did. They actually patented the process. The paper is from 1974 — you should have it in your handouts — it's in the Welding Journal, April '74. It was presented at a conference in 1973. The patent is 1972. You can't publish something and then patent it; you have to apply for the patent and then publish it.