Cyclic plastic behavior of additively manufactured Ti-6Al-4V under uniaxial and multiaxial non-proportional loading

摘要

Cyclic plastic behavior of additively manufactured Ti-6Al-4V titanium alloy was experimentally investigated under non-proportional multiaxial cyclic loading. Four cylindrical hollow specimen types were fabricated using laser powder bed fusion (L-PBF). The typology of each specimen was defined by the orientation of the layers and application of a stress-relief heat treatment post production. Then, the specimens' microstructures were analyzed. Stress strain cyclic testing in the specimens' plastic region resulted in near-equivalent curves for each fabricated specimen type. Fatigue tests evidenced that the fatigue life was similar regardless of heat-treatment and layer orientation. Hysteresis loops showed a higher energy absorption for the heat-treated components. Drastic softening has been detected in the majority of the tests and cracks initiating from internal voids, internal defects and surface could be observed.