Naval Research Laboratory fatigue-creep interaction cracking

NRL eventually solved the creep-fatigue interaction problem in heavy-section titanium that the Soviets had hit but not understood. Demonstrates that fundamental science can leapfrog empirical practice.

I had a couple students in the early '80s. I told you about Dan, who's in your program — eventually retired as Captain at Pearl Harbor. Dan did his master's thesis on, I think, high-speed movies, looking at the metal transfer, how little drops of metal melt off — the unstable processes that wouldn't work. Ten years later, that was retired between us. Hydrogen cracking, due to creep-fatigue interaction cracking — not hydrogen cracking, but the fact that the metal, if you put it under a constant compressive stress and then cycle it, you build broad cracks in the middle. So the metal itself, that's what you find out.

NRL's prior identification of the creep-fatigue cracking phenomenon in titanium under compression; the technical knowledge that made the Soviet Alpha-class outcome predictable in retrospect.

I had been working on welding heavy-section titanium since 1977, three years earlier. So all of a sudden I come back and a number of people want to talk to me, because ONR had been funding me to weld heavy-section titanium. They had some conferences down at David Taylor, in Carderock — I'll tell you more of those stories when we get to titanium. But I remember the guys from the Naval Research Lab said, Tom, how do they solve the creep-fatigue interaction in titanium? I kind of shrugged my shoulders, because I hardly even knew what the creep-fatigue interaction was. But the Office of the Naval Research Laboratory knew.