METHOD FOR STABILIZING SHAPE MEMORY CHARACTERISTIC OF SHAPE MEMORY TI-NI ALLOY

摘要

PURPOSE:To stabilize the shape memory characteristics of a shape memory alloy by selectively accumulating dislocation in the grains of the alloy so as to increase the dislocation density in the grains and to keep the dislocation density on the grain boundaries low. CONSTITUTION:Stock for a shape memory alloy is made to memorize a prescribed shape (a). The stock is so largely elongated as to cause plastic deformation (b). The load is relieved from the stock and the shape of the stock is restored by heating to the Md point or above at which restoration recrystallization is not caused or is hardly caused (c). The stock is rapidly cooled (d). The stages (b), (c), (d) are repeatedly carried out until the restored shape is stabilized.