| In previous researeh, martensitic transformation start temperature of 35Ti-50Ni-15Hf alloy was highest among (50-X)Ti-Ni-XHf(X = 0∼20 at.%) alloys. In this research, shape memory characteristics of (85-X) Ti-XNi-15Hf(X = 48∼51 at.%) alloys were investigated by means of X-ray diffractometry, differential scanning calorimetry and thermal cycling test under constant load. Stress dependence of tranaformation temperature was increased with increasing Ni content. The maximum recoverable elongation was decreased with increasing Ni content. Residual elongation did not occur under applied stress of 120 MPa in broth 36Ti-49Ni-l5Hf and 35Ti-5ONi-15Hf alloys. Aging temperature dependence of transformation temperature in 37Ti-48Ni-15Hf, 36Ti-49Ni-15Hf, 35Ti-50Ni-15Hf and 40Ti-50Ni-10Zr alloys was lower than that of a Ti-Ni binary alloy. Thermal cycling dependence of transformation temperature in a 37Ti-48Ni-15Hf alloy was lower than that of a 40Ti-50Ni-10Zr alloy. |
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