ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
In this study, we performed the bending fatigue test and investigated the influence ofstrain ratio on fatigue life in TiNi shape memory thin wire. The pulsating plane bending, alternatingplane bending and rotating bending fatigue tests were carried. Additionally, we carried out theobservation of the fatigue fracture surface by a scanning electron microscope. The behavior offatigue crack was investigated. The results obtained are summarized as follows. (1) The martensitictransformation (MT) stress of the superelastic thin wire (SE-NT) is higher than that of the SMA thinwire (SME-NT) and the fatigue life of SE-NT is shorter than that of SME-NT. Maximum bendingstrain at the fatigue limit is the MT starting strain. (2) The low-cycle fatigue life curve in planebending for SE-NT is expressed by a power function of maximum strain εmax and the number ofcycles to failure Nf. The smaller the strain ratio for the same εmax, the shorter the fatigue life. (3) Inboth the rotating bending and the plane bending, fatigue cracks nucleate on the surface of the wireand one fatigue crack grows preferentially. The region in which fatigue crack propagated isfan-shaped
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.340-341.1193.pdf
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