Compressive deformation behavior of AZ31 alloy at 21K; An neutron diffraction study

Gong, W.; Kawasaki, Takuro; Zheng, R.*; Mayama, Tsuyoshi*; Sun, B.*; Aizawa, Kazuya; Harjo, S.; Tsuji, Nobuhiro*

Scripta Materialia, 225, p.115161_1 - 115161_5, 2023/03

https://doi.org/10.1016/j.scriptamat.2022.115161

Regulation of strength and ductility of single-phase twinning-induced plasticity high-entropy alloys

Wei, D.*; Gong, W.; Kawasaki, Takuro; Harjo, S.; Kato, Hidemi*

Scripta Materialia, 216, p.114738_1 - 114738_6, 2022/07

https://doi.org/10.1016/j.scriptamat.2022.114738

Artificial neural network molecular mechanics of iron grain boundaries

Shiihara, Yoshinori*; Kanazawa, Ryosuke*; Matsunaka, Daisuke*; Lobzenko, I.; Tsuru, Tomohito; Koyama, Masanori*; Mori, Hideki*

Scripta Materialia, 207, p.114268_1 - 114268_4, 2022/01

https://doi.org/10.1016/j.scriptamat.2021.114268

This study reports grain boundary (GB) energy calculations for 46 symmetric-tilt GBs in -iron using molecular mechanics based on an artificial neural network (ANN) potential and compares the results with calculations based on the density functional theory (DFT), the embedded atom method (EAM), and the modified EAM (MEAM). The results by the ANN potential are in excellent agreement with those of the DFT (5% on average), while the EAM and MEAM significantly differ from the DFT results (about 27% on average). In a uniaxial tensile calculation of GB, the ANN potential reproduced the brittle fracture tendency of the GB observed in the DFT while the EAM and MEAM mistakenly showed ductile behaviors. These results demonstrate the effectiveness of the ANN potential in calculating grain boundaries of iron, which is in high demand in modern industry.

Role of retained austenite in low alloy steel at low temperature monitored by neutron diffraction

Yamashita, Takayuki; Morooka, Satoshi; Harjo, S.; Kawasaki, Takuro; Koga, Norimitsu*; Umezawa, Osamu*

Scripta Materialia, 177, p.6 - 10, 2020/03

https://doi.org/10.1016/j.scriptamat.2019.10.002

Neutron computed tomography of phase separation structures in solidified Cu-Co alloys and investigation of relationship between the structures and melt convection during solidification

Shoji, Eita*; Isogai, Shosei*; Suzuki, Rikuto*; Kubo, Masaki*; Tsukada, Takao*; Kai, Tetsuya; Shinohara, Takenao; Matsumoto, Yoshihiro*; Fukuyama, Hiroyuki*

Scripta Materialia, 175, p.29 - 32, 2020/01

https://doi.org/10.1016/j.scriptamat.2019.08.041

Deformation of CoCrFeNi high entropy alloy at large strain

Wang, B.*; He, H.*; Naeem, M.*; Lan, S.*; Harjo, S.; Kawasaki, Takuro; Nie, Y.*; Wang, X.-L.*; 7 of others*

Scripta Materialia, 155, p.54 - 57, 2018/10

https://doi.org/10.1016/j.scriptamat.2018.06.013

Effect of twin boundary on crack propagation behavior in magnesium binary alloys; Experimental and calculation studies

Somekawa, Hidetoshi*; Tsuru, Tomohito

Scripta Materialia, 130, p.114 - 118, 2017/03

https://doi.org/10.1016/j.scriptamat.2016.11.022

The impact of alloying elements on crack propagation and atomistic phenomenon at {102}-type twin boundaries in magnesium was investigated via both experiments and calculations. The alloying elements clearly affected crack propagation behavior. Cracks were difficult to propagate along matrix-deformation twinning interfaces in alloys that had high fracture toughness. In such magnesium alloys, the solute atoms, e.g., silver, manganese and zinc atoms, create adhesive interactions between magnesium atoms. Closed-shell and covalent-like bonding of these kinds of solute atoms would influence strong adhesion, which impedes the nucleation of a new surface at the twin boundary.

Evaluation of compressive deformation behavior of ZrAlNiCu bulk metallic glass containing ZrC particles by synchrotron X-ray diffraction

Suzuki, Hiroshi; Saida, Junji*; Shobu, Takahisa; Katsuyama, Jinya; Kato, Hidemi*; Imafuku, Muneyuki*; Sato, Shigeo*

Scripta Materialia, 66(10), p.801 - 804, 2012/05

https://doi.org/10.1016/j.scriptamat.2012.02.016

Compressive deformation mechanism of a ZrAlNiCu bulk metallic glass containing 10vol.%ZrC (ZrC-BMG) was evaluated by measuring the residual strains in the compressive deformed samples using the synchrotron X-ray diffraction and also evaluating the localized deformation behavior around the ZrC particles by the finite element analysis. Phase stress shared by the metallic glass matrix was increased before macroscopic yielding due to local plastic deformation around the ZrC particles. After macroscopic yielding, the phase stress shared by the ZrC phase was drastically increased, and finally the ZrC-BMG was fractured by breaking the ZrC particles reaching its fracture strength.

Bainitic transformation behavior studied by simultaneous neutron diffraction and dilatometric measurement

Koo, M.*; Xu, P. G.; Tomota, Yo*; Suzuki, Hiroshi

Scripta Materialia, 61(8), p.797 - 800, 2009/10

https://doi.org/10.1016/j.scriptamat.2009.06.032

Bainitic transformation behavior has firstly been observed using in situ neutron diffraction with an angular dispersive method for a hard bainite steel. The dilatometric measurement was carried out simultaneously with the neutron experiment where changes in (1 1 1) austenite and (1 1 0) ferrite diffraction profiles were monitored during heating, cooling and holding at a transformation temperature. The neutron experiments results agree with dilatometry results. They appear to have found that the austenite peak broadening occurs after the onset of bainitic transformation but not before.

Direct observation of hydrogen trapped by NbC in steel using small-angle neutron scattering

Onuma, Masato*; Suzuki, Junichi; Wei, F.*; Tsuzaki, Kaneaki*

Scripta Materialia, 58(2), p.142 - 145, 2008/01

https://doi.org/10.1016/j.scriptamat.2007.09.026

no abstracts in English