| 摘要 |
PURPOSE:To provide a thermosensitive device which has an extremely small hysteresis range and good repetitive service life characteristics by forming an NiTi shape memory alloy in such a way that the two-way motion combined with bias load is the displacement to change the crystal structure of the alloy from a cubic crystal to a rhombohedral crystal when cool and is the displacement reverse thereto when heated. CONSTITUTION:This invention is obtd. as a result of studying the relation between the hysteresis and service life of the two-way motion of a shape memory alloy (MSA) consisting of an NiTi alloy system. More specifically, the two-way motion combining bias load with said MSA is made into the displacement by the transformation of the crystal structure of said MSA changing from a cubic crystal (B2 phase) to a penta-rhombohedral crystal (R phase) when cool and to the displacement by the transformation restoring the B2 phase from the R phase when heated. The provision of the intended thermosensitive device of which the hysteresis of the two-way direction is <=3 deg.C and the change of the working temp. and permanent set in fatigue are considerably decreased in the repetitive service life is made possible by the above-mentioned limitation of the motion.
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