LAUSR

Abstract Spark plasma sintering was used to fabricate two Ti-25Zr-25Nb β-titanium alloys having a homogeneous microstructure and a so-called harmonic structure. Mechanical properties were evaluated by simple shear cyclic tests. The sample with homogeneous microstructure shows a large cumulative strain ~ 400% and a two-stage work-hardening associated with intense {332}〈113〉 mechanical twinning activity. Conversely, the harmonic-designed microstructure exhibits lesser cumulative strain ~ 200% but a higher cyclic strength. A complete twinning inhibition is observed. Indeed, the ultrafine-grained shell of the harmonic structure dispersed stress concentration. It accommodates plastic incompatibilities due to grain size difference by accumulating geometrically necessary dislocations at the shell/core vicinity.