Abstract
The nitrogen ion was implanted to TiNi shape memory alloy wires, and the influence of implantation treatment on the phase transformation temperature, tensile deformation and bending fatigue properties was investigated. The results obtained are summarized as follows. (1) If the dose of ion implantation increases, the reverse transformation temperature increases. (2) The larger the bending strain amplitude, the shorter the fatigue life is. If the strain amplitude is 4 %, the fatigue lives of all wires are almost the same. If the bending strain amplitude is small, the fatigue life becomes longer in the case of higher dose of ion implantation. (3) The fatigue crack nucleates at a certain point on the surface of the wire. In the case of higher ion implantation in the region of small strain amplitude, the fatigue crack initiation point differs from the maximum bending strain point, resulting in longer fatigue life.
