Yuji Sutou

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