PURPOSE: To manufacture an Ni-Ti superelastic material good in formability by executing sintering after cold working and heat treatment after forming to an Ni-Ti alloy having a specified componental compsn. under specified conditions.
CONSTITUTION: The Ni-Ti alloy contg., by atom, 50 to 51.5% Ni, and the balance Ti, or an Ni-Ti alloy contg. 49.5 to 51.5% Ni and total ≤1.8% of one or ≥ two kinds among Fe, Co, Cr, V, Pb, Al, Cu and Nb, and the balance Ti is prepd. This alloy is subjected to cold working, thereafter, annealed in the temp. range of 600 to 800°C for 3 to 60min, subjected to the forming to form its shape into a required one, and is subjected to heat treatment in the temp. range of 250 to 320°C for 20 to 200min. In this way, the objective Ni-Ti superelastic material having nallow stress hysteresis and small residual strain can be obtd.
MATSUBARA KAZUO
MURAYAMA YASUTO
