京都大学 · Materials Science
Kyosuke Kishida 교수의 연구실은 희토류를 포함한 다성분 체계에서의 고순도 금속 간 화합물, 특히 TiAl계 및 Mg-Al-RE계의 다상 합금에서의 나노구조 형성, 계면 거동, 그리고 온도 및 크기 효과에 따른 기계적 거동을 중심으로 연구를 수행하고 있습니다. 주로 전자현미경 기법을 활용해 고체 상태에서의 상전이, 오더-디스오더 구조의 형성 메커니즘과 그 기계적 거동의 이방성 원리를 규명하고 있으며, 나노스케일에서의 비틀림, 미세결정, 그리고 비정질 구조의 형성 메커니즘을 깊이 있게 분석하고 있습니다. 특히, 크기 효과에 따른 비틀림 및 미세결정의 기계적 강도 변화를 정량적으로 규명하는 데 초점을 맞추고 있습니다.
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The plastic deformation behavior of commercially pure Ti single crystals has been investigated by uniaxial micropillar compression tests as a function of crystal orientation and specimen size at room temperature. {101¯1} (first-order) pyramidal c+a slip and prism a slip are activated in micropillar specimens with the [0001] and [21¯1¯0] orientations, respectively. {101¯1} pyramidal c+a slip has never been observed to operate as a major deformation mode in compression tests of ‘bulk’ single cryst
Polysynthetically twinned (PST) crystals of TiAl(γ)-Ti3Al(α2) two-phase alloys with five different orientations were deformed in compression and in tension in the temperature range from- 196 to 1100°C. Deformation structures in gamma domains of six different orientation variants in each specimen were examined by transmission electron microscopy, and operative slip and/or twinning systems were determined. No significant change in the operative deformation modes was observed up to 800°C. On the ba
Polysynthetically twinned (PST) crystals of TiAl(γ)-Ti3Al(α2) two-phase alloys with five different orientations were deformed in compression and in tension in the temperature range from- 196 to 1100°C. Deformation structures in gamma domains of six different orientation variants in each specimen were examined by transmission electron microscopy, and operative slip and/or twinning systems were determined. No significant change in the operative deformation modes was observed up to 800°C. On the ba
The most stable crystal structure for an 18R-type order-disorder (OD) intermetallic phase in the Mg–Al–Gd ternary system and its formation processes by annealing at 525 °C have been investigated by means of transmission electron microscopy and scanning transmission electron microscopy. The most energetically favourable polytype at 525 °C is found to be the structurally simplest one, a maximum degree of order polytype (monoclinic, 1M, space group: C2/m), described with a single stacking vector in
The room-temperature plastic deformation behavior of 6HSiC single crystals has been investigated by uniaxial compression of micropillar specimens as a function of crystal orientation and specimen size. Plastic flow is observed even at room temperature by basal and prism slip, latter of which have never been observed in the bulk. The CRSS values for basal and prism slip are as high as above 5 and 6 GPa at the specimen size of 5 mm, respectively, each of which increases with decreasing specimen si
