Tohoku University · 재료과학
유지 츠우 교수의 연구실은 주로 헤이즐러 합금을 포함한 금속 합금의 상변화 거동과 그에 따른 기계적·자기적 특성 제어를 핵심으로 합니다. 특히 자성형 기억합금(Ferroelastic Shape Memory Alloys)과 구리계 기억합금의 초구조 제어, 나노구조 형성, 그리고 의료용 기구(예: 카디오세션 가이드와이어) 응용을 위한 기능성 구조 설계에 중점을 두고 있습니다. 연구는 상변화 거동 분석, 미세구조 제어, 그리고 기계적 성질 최적화를 통해 실용적 응용 가능성을 높이고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Martensitic and magnetic transformations of the Heusler Ni50Mn50−yXy (X=In, Sn and Sb) alloys were investigated by differential scanning calorimetry measurement and the vibrating sample magnetometry technique. In all these alloy systems, the austenite phase with the ferromagnetic state was transformed into the martensite phase, which means that these Heusler alloys have potential as Ga-free ferromagnetic shape memory alloys (FSMAs). Furthermore, multiple martensitic transformations, such as two-
Mechanical properties of Fe–20Mn–(10–14)Al–(0–1.8)C (mass%) quaternary and Fe–20Mn–(10–14)Al–(0.75–1.8)C–5Cr (mass%) quinary alloys were investigated by hardness, cold-workability and tensile tests at room temperature. The γ(fcc) alloys in both quaternary and quinary systems with a low density of less than 7.0 g/cm3 showed an excellent ductility and their hardness and tensile strength increased with increasing Al and C contents. The γ+α(bcc) duplex alloys also exhibited a high tensile strength b
Polycrystalline Cu–Al–Mn shape memory alloys (SMAs) with a low degree of order of the β (L2 1 ) phase show excellent ductility and exhibit shape memory (SM) properties such as superelasticity, the one way memory effect and the two way memory effect based on martensitic transformation. These SM properties can be greatly enhanced by controlling microstructural factors such as grain size and texture by thermomechanical treatments. In the present paper, the SM properties of ductile Cu–Al–Mn based SM
Tensile and compressive stress–strain characteristics for Ni–Ga–Fe ferromagnetic shape memory alloys at several temperatures were investigated by mechanical test and a critical stress versus temperature diagram was obtained. The crystal structure of the martensite phase obtained by tensile-stress-induced martensitic transformation was estimated from the degree of the transformation strain. Stress-induced martensite transformed from the parent phase with an L21 structure showed a 14M structure by
A new type of medical guide wire with functionally graded hardness from the tip to the end was developed with the use of Cu-Al-Mn-based alloys. The superelasticity (SE) of the Cu-Al-Mn-based alloys in the tip is drastically improved by controlling the grain size, whereas the end of the wire is hardened using bainitic transformation by aging at around 200-400 degrees C. Therefore, the tip of the guide wire shows a superelasticity and its end has high stiffness. This guide wire with functionally g
