Oxygen interstitials make metastable titanium alloys strong and ductile

Chong, Y.*; Gholizadeh, R.*; Guo, B.*; Tsuru, Tomohito; Zhao, G.*; Yoshida, Shuhei*; Mitsuhara, Masatoshi*; Godfrey, A.*; Tsuji, Nobuhiro*

Acta Materialia, 257, p.119165_1 - 119165_14, 2023/09

https://doi.org/10.1016/j.actamat.2023.119165

Metastable titanium alloys possess excellent strain-hardening capability, but suffer from a low yield strength. As a result, numerous attempts have been made to strengthen this important structural material in the last decade. Here, we explore the contributions of grain refinement and interstitial additions in raising the yield strength of a Ti-12Mo (wt.%) metastable titanium alloy. Surprisingly, rather than strengthening the material, grain refinement actually lowers the ultimate tensile strength in this alloy. This unexpected and anomalous behavior is attributed to a significant enhancement in strain-induced martensite phase transformation, where in-situ synchrotron X-ray diffraction analysis reveals, for the first time, that this phase is much softer than the parent phase. Instead, a combination of both oxygen addition and grain refinement is found to realize an unprecedented strength-ductility synergy in a Ti-12Mo-0.3O (wt.%) alloy. The advantageous effect of oxygen solutes in this ternary alloy is twofold. Firstly, solute oxygen largely suppresses strain-induced transformation to the martensite phase, even in a fine-grained microstructure, thus avoiding the softening effect of excessive amounts of martensite. Secondly, oxygen solutes readily segregate to twin boundaries, as revealed by atom probe tomography. This restricts the growth of deformation twins, thereby promoting more extensive twin nucleation, leading to enhanced microstructural refinement. The insights from our work provide a cost-effective rationale for the design of strong yet tough metastable titanium alloys, with significant implications for more widespread use of this high strength-to-weight structural material.

On the design of experiments to study extreme field limits

Bulanov, S. S.*; Chen, M.*; Schroeder, C. B.*; Esarey, E.*; Leemans, W. P.*; Bulanov, S. V.; Esirkepov, T. Z.; Kando, Masaki; Koga, J. K.; Zhidkov, A. G.*; et al.

AIP Conference Proceedings 1507, p.825 - 830, 2012/12

https://doi.org/10.1063/1.4773805

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in and Au+Au collisions at = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

https://doi.org/10.1103/PhysRevC.83.044912

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.

High RF power test of a lower hybrid module mock-up in carbon fiber composite

Maebara, Sunao; ; Seki, Masami; Suganuma, Kazuaki; Ikeda, Yoshitaka; Imai, Tsuyoshi; Goniche, M.*; J.Brossaud*; V.Cano*; F.Kazarian-Vibert*; et al.

JAERI-Research 97-086, 29 Pages, 1997/11

JAERI-Research-97-086.pdf:1.33MB

no abstracts in English

Performance test of lower hybrid waveguide under long/high-RF power transmission

Seki, Masami; Obara, Kenjiro; Maebara, Sunao; Ikeda, Yoshitaka; Imai, Tsuyoshi; Nagashima, Takashi; Goniche, M.*; J.Brossaud*; C.Barral*; G.Berger-By*; et al.

JAERI-Research 96-025, 55 Pages, 1996/06

JAERI-Research-96-025.pdf:2.06MB

no abstracts in English

Outgassing measurement of the waveguide module for a steady state LHCD antenna

Seki, Masami; Obara, Kenjiro; Maebara, Sunao; Ikeda, Yoshitaka; Imai, Tsuyoshi; Nagashima, Takashi; Goniche, M.*; J.Brossaud*; C.Barral*; G.Berger-By*; et al.

Fusion Engineering and Design, 30, p.357 - 367, 1995/00

https://doi.org/10.1016/0920-3796(95)00413-F

no abstracts in English