What's New
2023（January－June）
-
2023.6.29
-
2023.6.23
-
2023.6.9
-
2023.5.22
-
2023.4.30
-
2023.4.12
-
2023.3.23
-
2023.1.11
-
2023.6.29
A paper on guidelines for controlling the crystal aggregation structure of metastable beta Ti alloys by LPBF has been published as an OA paper in Materials Letters (IF=3.574).
Takuya Ishimoto, Ryoya Suganuma and Takayoshi Nakano*:
Tailoring the crystallographic texture of biomedical metastable β-type Ti-alloy produced via laser powder bed fusion using temperature-field simulations,
Materials Letters, 349, (2023), 134835; 1-4.
https://doi.org/10.1016/j.matlet.2023.134835click here for this paper.
Abstract
Recently, the use of laser powder bed fusion (LPBF) to create crystallographic textures, such as single-crystal-like and polycrystalline textures, has attracted attention. However, the relationship between the LPBF conditions and the resulting texture is unclear. This study investigates the effects of the LPBF conditions (laser power and scanning speed) on the texture by estimating the solidification behavior using temperature-field simulations. Herein, we show for the first time that laser power and scanning speed negatively and positively affect the so1lidification rate R, respectively, and do not affect the thermal gradient G significantly. Thus, when the laser power decreases and scanning speed increases, the G/R ratio decreases and polycrystal formation is enhanced. This is consistent with practical observations.Keywords
Laser powder bed fusion, Crystallographic texture, Single crystal, Polycrystal, Temperature simulation
-
2023.6.23
Next-generation catalysts with high activity, high selectivity, and high temperature durability were successfully prepared by laser metal 3D printing and published as an OA paper in Advanced Functional Materials (IF=19.9).
Hyo-Jin Kim, Kohsuke Mori*, Takayoshi Nakano, Hiromi Yamashita:
Robust Self-Catalytic Reactor for CO2 Methanation Fabricated by Metal 3D Printing and Selective Electrochemical Dissolution,
Advance Functional Materials, (2023), 2303994; 1-21.
https://doi.org/10.1002/adfm.202303994click here for this paper.
Abstract
The methanation of CO2 has been actively pursued as a practical approach to mitigating global climate change. However, the complexity of the catalyst development process has hindered the development of new catalysts for CO2 methanation; as a result, few catalysts are commercially available. Herein, a multifunctional self-catalytic reactor (SCR) is prepared via metal 3D printing and selective electrochemical dissolution as a method to not only simplify the catalyst development process but also fabricate active catalysts for CO2 methanation. The combination of metal 3D printing and selective electrochemical dissolution is demonstrated as a feasible method to prepare active catalysts for the methanation of CO2 in a short time. In addition, the use of an electrochemical method enables the formation of galvanic cells on the SCR; these cells continuously generate active sites via self-dissolution during a simple refresh process, resulting in high reusability of the SCR. The proposed method represents a new facile technique to fabricate highly reusable catalysts that exhibit superior performance for CO2 methanation, and the results provide a guideline for preparing metal 3D-printed catalysts that will satisfy industrial demand. -
2023.6.9
Metals (IF=2.695) published a paper on soluble intermetallic compounds as an OA paper.
Koji Hagihara*, Shuhei Shakudo, Toko Tokunaga, Takayoshi Nakano:
Development of Zn-Mg-Ca biodegradable dual-phase alloys,
Metals, 13 [6], (2023), 1095; 1-13.
https://doi.org/10.3390/met13061095click here for this paper.
Abstract
In this paper, in order to achieve the development of a novel biodegradable dual-phase alloy in a Ca-Mg-Zn system, the establishment of the control strategy of degradation behavior of alloys composed of two phases was attempted by the control of alloy composition, constituent phases, and microstructure. By combining two phases with different dissolution behavior, biodegradable alloys are expected to exhibit multiple functions. For example, combining a suitable slow dissolving phase with a faster dissolving second phase may allow for dynamical concavities formation during immersion on the surface of the alloy, assisting the invasion and establishment of bone cells. Without the careful control of the microstructure, however, there is a risk that such dual-phase alloy rapidly collapses before the healing of the affected area. In this study, ten two-phase alloys consisting of various different phases were prepared and their degradation behaviors were examined. Consequently, it was found that by combining the IM3 and IM1 intermetallic phases with the compositions of Ca2Mg5Zn13 and Ca3Mg4.6Zn10.4, the expected degradation behavior can be obtained.
Keywords: biodegradable metallic material; dual-phase alloy; intermetallic compound; degradation behavior -
2023.5.22
Frontiers in Earth Science-Paleontology (IF=3.661) has published an article on "Life history evolution of insular dwarfism" as an OA article.
Shoji Hayashi*, Mugino O. Kubo*, Marcelo R Sanchez, Hiroyuki Taruno, Masako Izawa, Tsunehiro Shiroma, Takayoshi Nakano and Masaki Fujita:
Variation and process of life history evolution in insular dwarfism as revealed by a natural experiment,
Frontiers in Earth Science-Paleontology, (2023), in press.
https://doi.org/10.3389/feart.2023.1095903click here for this paper.
-
2023.4.30
A paper on X-scan 3D image construction of SUS316L stainless steel formed by AM was published in Journal of Imaging.
Keiya Sugiura, Toshio Ogawa, Yoshitaka Adachi*, Fei Sun, Asuka Suzuki, Akinori Yamanaka, Nobuo Nakada, Takuya Ishimoto, Takayoshi Nakano, Yuichiro Koizumi:
Big-Volume SliceGAN for Improving a Synthetic 3D Microstructure Image of Additive-Manufactured TYPE 316L Steel,
Journal of Imaging, 9 [5], (2023), 90; 1-12.
DOI: https://doi.org/10.3390/jimaging9050090click here for this paper.
Abstract: A modified SliceGAN architecture was proposed to generate a high-quality synthetic three-dimensional (3D) microstructure image of TYPE 316L material manufactured through additive methods. The quality of the resulting 3D image was evaluated using an auto-correlation function, and it was discovered that maintaining a high resolution while doubling the training image size was crucial in creating a more realistic synthetic 3D image. To meet this requirement, modified 3D image generator and critic architecture was developed within the SliceGAN framework.
Keywords: SliceGAN; generative adversarial network; synthetic 3D image; additive manufacturing; autocorrelation function
-
2023.4.12
A collaborate research paper with Northeastern University on beta-titanium alloys containing high concentrations of Zr has been published as an OA paper in the Journal of Alloys and Compounds (JALCOM) (IF=6.371).
Xiaoli Zhao*, Rongxin Zhu, Wenke Song, Lei Meng, Mitsuo Niinomi, Takayoshi Nakano, Nan Jia, Deliang Zhang:
A strategy to regulate the yield ratio of a metastable high Zr-containing β titanium alloy: Synergistic effects of the β domain, β stability and β/α interfaces by varying the α phase content,
Journal of Alloys and Compounds, 952, (2023), 170024; 1-13.
https://doi.org/10.1016/j.jallcom.2023.170024click here for this paper.
Abstract
To meet the demands of both processing and serving, to the best of our knowledge, this is the first report exhibiting large range control of the yield ratio from 0.31 to 0.96 with decent elongations over 10% in the same alloy with low-cost thermal treatments. The yield ratio of the metastable Ti-30Zr-5Mo alloy was regulated via adjusting trigger stress of the stress-induced phase transformation and work-hardening ability through changing the α phase content. Materials with acicular α phase of different contents were successfully prepared via low-cost thermal treatment. The effects of the α phase content on the stress-induced α' martensite phase transformation and work hardening behavior were then investigated. In the Ti-30Zr-5Mo alloy with dual phases, due to the crystal difference and element partitioning, the hardness of the α phase is higher than that of the β matrix, and the hardness difference between the phases increases with increasing α phase. In addition to Mo, Zr plays an important role in stabilizing the β phase in high-Zr-containing alloys. Deformation initiates in the β phase of both single-phase and duplex-phase alloys. The deformation mechanism of the β phase is dependent on both the β domain and β stability. Due to the low trigger stress and excellent work hardening ability, stress-induced α' martensite phase transformation is helpful to lower the yield ratio. As the α phase content increases, the trigger stress increases, and when the α phase content increases to 40%, dislocation slip dominates rather than stress-induced α' martensite phase transformation, and a high yield strength of 944 MPa is obtained. The α/β phase interfaces act as effective obstacles to hinder dislocation movement and provide working hardening, and the obstruction effect is more significant with an increase in the hardness difference between the α and β phases. The stress-induced α' phase transformation and/or the deformation coordination between the α and β phases guarantee decent elongations of no less than 10% in the large control of the yield ratio from 0.31 to 0.96 with a yield strength from 254 to 1013 MPa. It paves the way to develop "Unititaniam" alloys for wide possible applications. -
2023.3.23
A paper on the demonstration of intervertebral spacers capable of inducing bone orientation has been published as an OA article in The Spine Journal.
Aira Matsugaki, PhD, Manabu Ito, MD, PhD, Yoshiya Kobayashi, Meng, Tadaaki Matsuzaka, Meng, Ryosuke Ozasa, PhD, Takuya Ishimoto, PhD, Hiroyuki Takahashi, PhD, Ryota Watanabe, Meng, Takayuki Inoue, PhD, Katsuhiko Yokota, BA, Yoshio Nakashima, Meng, Takashi Kaito, MD, PhD, Seiji Okada, MD, PhD, Takao Hanawa, PhD, Yukihiro Matsuyama, MD, PhD, Morio Matsumoto, MD, PhD, Hiroshi Taneichi, MD, PhD, Takayoshi Nakano*, PhD:
Innovative design of bone quality-targeted intervertebral spacer: Accelerated functional fusion guiding oriented collagen/apatite microstructure without autologous bone graft,
The Spine Journal, 23, (2023), 609-620.
DOI: https://doi.org/10.1016/j.spinee.2022.12.011[Abstract]
●BACKGROUND CONTEXT
Although autologous bone grafting is widely considered as an ideal source for interbody fusion, it still carries a risk of nonunion. The influence of the intervertebral device should not be overlooked. Requirements for artificial spinal devices are to join the vertebrae together and recover the original function of the spine rapidly. Ordered mineralization of apatite crystals on collagen accelerates bone functionalization during the healing process. Particularly, the stable spinal function requires the ingrowth of an ordered collagen and apatite matrix which mimics the intact intervertebral microstructure. This collagen and apatite ordering is imperative for functional bone regeneration, which has not been achieved using classical autologous grafting.
●PURPOSE
We developed an intervertebral body device to achieve high stability between the host bone and synthesized bone by controlling the ordered collagen and apatite microstructure.
●STUDY DESIGN
This was an in vivo animal study.
●METHODS
Intervertebral spacers with a through-pore grooved surface structure, referred to as a honeycomb tree structure, were produced using metal 3D printing. These spacers were implanted into normal sheep at the L2-L3 or L4-L5 disc levels. As a control group, grafting autologous bone was embedded. The mechanical integrity of the spacer/bone interface was evaluated through push-out tests.
●RESULTS
The spacer with honeycomb tree structure induced anisotropic trabecular bone growth with textured collagen and apatite orientation in the through-pore and groove directions. The push-out load of the spacer was significantly higher than that of the conventional autologous graft spacer. Moreover, the load was significantly correlated with the anisotropic texture of the newly formed bone matrix.
●CONCLUSIONS
The developed intervertebral spacer guided the regenerated bone matrix orientation of collagen and apatite, resulting in greater strength at the spacer/host bone interface than that obtained using a conventional gold-standard autologous bone graft.
●CLINICAL SIGNIFICANCE
Our results provide a foundation for designing future spacers for interbody fusion in human.[Keywords]
Bone quality, Collagen and apatite orientation, Intervertebral spacer, Push-out strength, Spinal fusion, Through-pore grooved surface structure -
2023.1.11
A paper on the control of crystal orientation structure by gas flow direction and the elucidation of the mechanism has been accepted for publication as an OA paper in Virtual and Physical Prototyping (IF=10.962).
Hiroki Amano, Takuya Ishimoto, Koji Hagihara, Ryoya Suganuma, Keisuke Aiba, Shi-Hai Sun, Pan Wang, Takayoshi Nakano*:
Impact of gas flow direction on the crystallographic texture evolution in laser powder bed fusion,
Virtual and Physical Prototyping, (2023), in press.