Novel Fatigue Tester for Additively Manufactured Metals

This paper proposes a dual function fatigue tester that can perform both the traditional four-point rotate bending and the new cantilever rotate bending fatigue test. The linear profile of the cantilever specimen, that is simplified from the theoretical cubic profile, is subjected to uniform stress along the entire gage length and alternating between tension and compression modes until fracture. The system is designed to operate at 50-60 Hz, which is much faster than the traditional 5-10Hz in traditional push-pull fatigue testing. Preliminary fatigue testing on wrought Inconel 718 cantilever specimen shows random fracture along the specimen gage length, and successfully separation of fatigue fractured surfaces for subsequent fractography analysis. The system will be utilized for studying fatigue of selective laser melted Inconel 718 and the effect of different post processing parameters.