Fracture Behaviors of Additive Manufactured Alloys

Advanced fracture mechanics behavior, especially at depressed, cryogenic temperatures has not been reported in the literature nor is it being pursued in current open efforts. A variety of alloy systems have issues when processed via additive manufacturing, if careful attention isn't paid. The nature of the processing, which is akin to millions of microwelds in a complex/re-heating environment, can cause the formation of deleterious secondary phases or alter the grain boundary chemistry/morphology. The simplest and best way to evaluate any susceptibility is to perform testing under the worst conditions that it will see, which for JPL's purposes, is cryogenic fatigue loading of Ti-6AI-4V. More »