ニッケルチタン形状記憶合金の超弾性機能疲労特性に及ぼす短時間形状記憶処理の効果

抄録

Present study concerns the functional fatigue due to the cycles of superelasticity in shape memory alloy. When superelasticity is repeated for large number of cycles, the functional fatigue would be observed as the accumulation of residual strain. As a result, the extent of superelastic strain decreases with increasing the number of cycles. First, present study found that as cold-drawn wire of Nickel Titanium alloy (50.6 at.% Ni) exhibits superelasticity after the heat treatment at 500℃ for a few ten seconds. We shall call this flash heating “short time aging”. Next, it was also found that the short time aged sample showed smaller amount of residual strain after the repetition of superelasticity. The amount of residual strain decreased with decreasing the period of aging.