Japan Science and Technology Agency

Terumo Kabushiki Kaisha

Other

Honda Motor Co., Ltd.

National Institute of Advanced Industrial Science and Technology

Yuuki Tanaka

Kiyohito Ishida

Ryosuke Kainuma

Yuji Sutou

Hiraku Murayama

Toshihiro Omori

Kiyoshi Yamauchi

Ryouichi Souba

Masahiro Ohta

Toru Sukigara

Katsunari Oikawa

A guide wire includes a distal core member made of a ferrous alloy which has shape memory properties and superelasticity. The ferrous alloy preferably includes substantially two phases, and has a difference of 100&#xb0; C. or less between an Af point and an Ms point in a thermal hysteresis of martensitic transformation and reverse transformation. The guide wire may include a proximal core member made of an iron-containing alloy and having a higher modulus of elasticity than the distal core member. The two core members may be joined together by welding to form a core of the guide wire.

Guide wire and stent

An iron-based alloy having shape memory properties and superelasticity, which has a composition comprising 25-35% by mass of Ni, 13-25% by mass of Co, 2-8% by mass of Al, and 1-20% by mass in total of at least one selected from the group consisting of 1-5% by mass of Ti, 2-10% by mass of Nb and 3-20% by mass of Ta, the balance being substantially Fe and inevitable impurities, and a recrystallization texture substantially comprising a &#x3b3; phase and a &#x3b3;' phase, particular crystal orientations of the &#x3b3; phase being aligned, and the difference between a reverse transformation-finishing temperature and a martensitic transformation-starting temperature being 100&#xb0; C. or less in the thermal hysteresis of martensitic transformation and reverse transformation.

Iron-based alloy having shape memory properties and superelasticity and its production method

A shape memory alloy comprises Co, Ni and Al with a two-phase structure comprising a &#x3b2;-phase having a B2 structure and a &#x3b3;-phase having an fcc structure, at least 40% by area of crystal grain boundaries of the &#x3b2;-phase being occupied by the &#x3b3;-phase. The shape memory alloy can be produced by a first heat treatment step comprising heating at 1200 to 1350&#xb0; C. for 0.1 to 50 hours and cooling at 0.1 to 1000&#xb0; C./minute, and a second heat treatment step comprising heating at 1000 to 1320&#xb0; C. for 0.1 to 50 hours and cooling at 10 to 10000&#xb0; C./minute.

Shape memory alloy and method for producing same

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Sendai, Japan

Yuuki Tanaka