Cyclic shear behavior of conventional and harmonic structure-designed Ti-25Nb-25Zr β-titanium alloy: Back-stress hardening and twinning inhibition. (September 2017)

• Record Type: Journal Article
• Authors: Dirras, G.; Ueda, D.; Hocini, A.; Tingaud, D.; Ameyama, K.
• Is Part Of: Scripta materialia. Number 138(2017)
• Page Start: 44
• Page End: 47
• Publication Date: 2017-09
• Subjects: Titanium alloys -- Spark plasma sintering -- EBSD -- Twinning -- Harmonic structure; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2017.05.033
• Languages: English
• ISSNs: 1359-6462

Abstract

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. Graphical abstract: