Unveiling the effects of Mn, Cr, Al, and Si on the low-temperature tempering behaviors of high-carbon martensite

Zhang, Y.*; Marusawa, Kenji*; Kudo, Kohei*; Morooka, Satoshi; Gong, W.; Harjo, S.; Miyamoto, Goro*; Furuhara, Tadashi*

Journal of Materials Science & Technology, 275, p.250 - 259, 2026/12

https://doi.org/10.1016/j.jmst.2026.04.015

Temperature-dependent deformation behavior of dual-phase medium-entropy alloy; In-situ neutron diffraction study

Gu, G. H.*; Jeong, S. G.*; Heo, Y.-U.*; Harjo, S.; Gong, W.; Cho, J.*; Kim, H. S.*; 4 of others*

Journal of Materials Science & Technology, 223, p.308 - 324, 2025/07

https://doi.org/10.1016/j.jmst.2024.11.057

Quantitative analysis of microstructure evolution, stress partitioning and thermodynamics in the dynamic transformation of Fe-14Ni alloy

Li, L.*; Miyamoto, Goro*; Zhang, Y.*; Li, M.*; Morooka, Satoshi; Oikawa, Katsunari*; Tomota, Yo*; Furuhara, Tadashi*

Journal of Materials Science & Technology, 184, p.221 - 234, 2024/06

https://doi.org/10.1016/j.jmst.2023.10.037

neutron diffraction revealing the achievement of excellent combination of strength and ductility in metastable austenitic steel by grain refinement

Mao, W.; Gong, W.; Harjo, S.; Morooka, Satoshi; Gao, S.*; Kawasaki, Takuro; Tsuji, Nobuhiro*

Journal of Materials Science & Technology, 176, p.69 - 82, 2024/03

https://doi.org/10.1016/j.jmst.2023.07.036

The yield stress of Fe-24Ni-0.3C (wt.%) metastable austenitic steel increased 3.5 times (158 551 MPa) when the average grain size decreased from 35 m (coarse-grained [CG]) to 0.5 m (ultrafine-grained [UFG]), whereas the tensile elongation was kept large (0.87 0.82). neutron diffraction measurements of the CG and UFG Fe-24Ni-0.3C steels were performed during tensile deformation at room temperature to quantitatively elucidate the influence of grain size on the mechanical properties and deformation mechanisms. The initial stages of plastic deformation in the CG and UFG samples were dominated by dislocation slip, with deformation-induced martensitic transformation (DIMT) also occurring in the later stage of deformation. Results show that grain refinement increases the initiation stress of DIMT largely and suppresses the rate of DIMT concerning the strain, which is attributed to the following effects. (i) Grain refinement increased the stabilization of austenite and considerably delayed the initiation of DIMT in the 111//LD (LD: loading direction) austenite grains, which were the most stable grains for DIMT. As a result, most of the 111//LD austenite grains in the UFG specimens failed to transform into martensite. (ii) Grain refinement also suppressed the autocatalytic effect of the martensitic transformation. Nevertheless, the DIMT with the low transformation rate in the UFG specimen was more efficient in increasing the flow stress and more appropriate to maintain uniform deformation than that in the CG specimen during deformation. The above phenomena mutually contributed to the excellent combination of strength and ductility of the UFG metastable austenitic steel.

Strengthening of high-entropy alloys via modulation of cryo-pre-straining-induced defects

Wei, D.*; Gong, W.; Wang, L.*; Tang, B.*; Kawasaki, Takuro; Harjo, S.; Kato, Hidemi*

Journal of Materials Science & Technology, 129, p.251 - 260, 2022/12

https://doi.org/10.1016/j.jmst.2022.04.055

Blue-shift in optical bandgap of sprayed nanocrystalline CuZnSnS thin films induced by 200 MeV Xe swift heavy ions irradiation

Khoualed, M.*; Boutebakh, F. Z.*; Chettah, A.*; Amekura, Hiroshi*; Ishikawa, Norito; Ghemid, S.*; Attaf, N.*; Aida, M. S.*

Journal of Materials Science; Materials in Electronics, 32(20), p.25516 - 25527, 2021/10

https://doi.org/10.1007/s10854-021-07017-8

CuZnSnS (CZTS) thin films deposited on glass substrate using spray pyrolysis technique were irradiated by 200 MeV Xe ions at different fluences. The effect of high-density electronic excitations on the properties of CZTS thin films has been examined using UV-visible spectrophotometry for optical properties, X-ray diffraction and Raman spectroscopy for structural properties. A pronounced blue-shift in the transmittance spectra edges and bandgap widening up to 2.05 eV were observed by the irradiation.

Atomistic simulations for the effects of stacking fault energy on defect formations by displacement cascades in FCC metals under Poisson's deformation

Hayakawa, Sho*; Okita, Taira*; Itakura, Mitsuhiro; Kawabata, Tomoya*; Suzuki, Katsuyuki*

Journal of Materials Science, 54(16), p.11096 - 11110, 2019/08

https://doi.org/10.1007/s10853-019-03688-1

Synthesis of multilayered composite nanotube heterostructure; SiC-SiO, C-SiO, and C-SiC-SiO nanotubes

Taguchi, Tomitsugu; Shamoto, Shinichi

Journal of Materials Science, 47(10), p.4363 - 4369, 2012/05

https://doi.org/10.1007/s10853-012-6290-9

Three types of composite nanotube heterostructures (two double-layered and one triple-layered structure) are synthesized by simple heat treatment, forming SiC-SiO, C-SiO, and C-SiC-SiO composite coaxial nanotubes. These multilayered composite nanotubes consist of several components with different electrical properties, for example, metal, semiconductor and insulator components. In particular, C-SiC-SiO triple-layered nanotubes with metallic, semiconducting and insulating layers are synthesized for the first time. These multilayered nanotubes can be expected to find applications in nanoscale heterostructure electronic and optical devices.

High-temperature pyrolysis of ceramic fibers derived from polycarbosilane-polymethylhydrosiloxane polymer blends with porous structures

Kita, Kenichiro; Narisawa, Masaki*; Nakahira, Atsushi*; Mabuchi, Hiroshi*; Ito, Masayoshi*; Sugimoto, Masaki; Yoshikawa, Masahito

Journal of Materials Science, 45(1), p.139 - 145, 2010/01

https://doi.org/10.1007/s10853-009-3905-x

The polymer blends of polycarbosilane (PCS) and polymethylohydrosiloxane with high molecular weight (PMHS-h) were prepared by freeze-drying process. Melt viscosity, themogravimetric analysis, and gas evolution from the polymer blends were analyzed. The polymer blend of HSah15 (15 mass% PMHS-h to PCS) was melt-spun to fiber form, curing by thermal oxidation and pyrolyzed at various temperatures up to 1773 K. The fibers were investigated by tensile tests, FE-SEM observation, and XRD (X-ray diffraction) analysis. After pyrolysis at 1273 K, there were amounts of pores in the cross sections of the fiber derived from HSah15, and after pyrolysis at 1773 K, no remarkable -SiC crystal were formed on the outside surface of the fiber derived from HSah15.

Carcinogen adsorbent prepared from DNA complex by -ray irradiation

Furusawa, Kazuya*; Kita, Erika*; Saeki, Toshihiko*; Nagasawa, Naotsugu; Nishi, Norio*; Dobashi, Toshiaki*

Journal of Biomaterials Science; Polymer Edition, 19(9), p.1159 - 1170, 2008/09

To insolubilize DNA for preparing a novel carcinogen adsorbent, effects of -ray irradiation on aqueous solutions of mixtures of DNA with cross-linking biopolymers (CBP): gelatin, bovine serum albumin, carboxymethyl cellulose and hydroxyethyl-cellulose, O-[2-hydroxy-3-(trimethyl ammonio)-propyl], chloride have been studied. DNA-CBP hybrid gels were successfully prepared from aqueous mixtures of DNA with CBP in a limited range of irradiation dose. Gel fraction (Gf) and swelling ratio (S) of the hybrid gels were measured. The Gf and S of hybrid gels increased and decreased, respectively, with increasing irradiated dose. Adsorption of one of carcinogen, acridine orange, was also examined for the gels. From the experimental results, the optimum condition for preparing insolubilized homogeneous DNA gels was determined.