日本金属学会誌
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
早期公開論文
早期公開論文の4件中1~4を表示しています
  • 高田 裕治, 杉山 拓弥, 湯山 道也, 埋橋 淳, 大久保 忠勝, 原田 広史, 鈴木 進補, 川岸 京子
    原稿種別: 技術論文
    論文ID: J2022036
    発行日: 2023年
    [早期公開] 公開日: 2023/01/27
    ジャーナル フリー 早期公開

    The influence of impurity element Sb on the oxidation resistance and creep strength of the single crystal superalloy TMS-238 was studied in this work. It was found that 1.1 ppm Sb clearly degrades the oxidation resistance, but not for the creep strength. As we increased the amount of Sb up to 3.8 ppm, the weight loss of the sample increased, as expected for the effect of Sb on the oxidation resistance. To understand the mechanism, the oxide structure was characterized by scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDS), and three-dimensional atom probe (3DAP) was used to visualize the Sb distribution. 3DAP analysis has revealed Sb segregation of 0.03 at% to 0.04 at% at the oxide/substrate interfaces for 3.8 ppm Sb sample. These results indicated that the segregation of Sb, a low melting point metallic impurity, at the oxide/substrate interface degrades the oxidation resistance for TMS-238.

  • 堀川 敬太郎, 鍬田 英樹, 福室 直樹, 日野 実
    原稿種別: 論文
    論文ID: JC202101
    発行日: 2023年
    [早期公開] 公開日: 2023/01/27
    ジャーナル フリー 早期公開

    In the present study, the effect of electro zinc plating on environmental hydrogen embrittlement of 7075-T6 aluminum alloys was investigated by using a slow strain rate testing device which can detect quantitively the amount of hydrogen generated during deformation and fracture. The testing device can also detect traces of hydrogen gas as low as 5 ppb by using a semiconductor gas sensor at ambient pressure. It was revealed that the environmental hydrogen embrittlement of 7075-T6 aluminum alloys was highly suppressed by zinc-based electroplating, while not fully by anodization. The suppression of the hydrogen embrittlement by zinc plating was caused by the protection of original aluminum surfaces during plastic deformation.

  • 沼倉 恭平, 大高 一将, 村上 武, 清水 一行, 鎌田 康寛, 妹尾 武, 岩瀬 義孝, 張 鐘植
    原稿種別: 論文
    論文ID: JBW202204
    発行日: 2023年
    [早期公開] 公開日: 2023/01/20
    ジャーナル フリー 早期公開

    The microstructures, Vickers hardness, and electromagnetic properties of the automotive die-quenched steel were investigated under various die temperatures. The positive correlations between hardness and the coercivity of magnetic hysteresis loop and between hardness and electrical resistance were confirmed above the hardness of HV370. EBSD and TEM observations reveal that the die-quenched steels contain both fresh martensite and auto-tempered martensite due to the high martensite transformation temperature of the steel. Neural network analysis shows an increase of auto-tempered martensite with increasing die-temperature, which causes the positive correlation. This study demonstrates the usefulness of nondestructive electromagnetic evaluation of the hardness in die-quenched automotive steel components during manufacturing process.

  • 小柴 佳子, 巽 宏平
    原稿種別: 論文
    論文ID: J2022039
    発行日: 2022年
    [早期公開] 公開日: 2022/12/28
    ジャーナル フリー 早期公開

    Power devices, such as power conversion and control devices, with excellent performance and high efficiency, are essential to realizing a carbon-neutral society. Towards that goal, devices using wide bandgap semiconductors, such as SiC and GaN, are being developed. Because wide bandgap semiconductors can operate at higher temperatures than conventional Si devices can, packaging technology with high heat resistance is required to demonstrate their performance. Previously, we proposed a sinter bonding technique using Ni nanoparticles for die bonding, i.e., bonding semiconductor chips to substrates. We demonstrate that Ni could be bonded to Al by sintering in the air. Meanwhile, the structures of recently reported power devices contain surface electrodes with an Al-Ni interface. Our research on Ni nanoparticle bonding and the Al–Ni interface in recent device structures demonstrated that evaluating the changes in the Al–Ni interface at high temperatures is crucial to ensure long-term reliability for high-temperature operation of the devices. Therefore, the diffusion behavior of Ni/Al multilayer samples annealed in air or vacuum was evaluated using Auger electron spectroscopy. Furthermore, the effect of the natural Al oxide film at the Ni/Al interface was also investigated. The results revealed that in the Ni/Al2O3/Al structure, atmospheric heating induced interdiffusion of Ni and Al through the Al oxide layer and that the natural Al oxide layer acted as a barrier to diffusion during vacuum heating.

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