Enhancement of fatigue life of Ni-Ti-Fe shape memory alloys by thermal cycling

Giri, Sushil K. ; Krishnan, Madangopal ; Ramamurty, U. (2010) Enhancement of fatigue life of Ni-Ti-Fe shape memory alloys by thermal cycling Materials Science and Engineering: A, 528 (1). pp. 363-370. ISSN 0921-5093

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/j.msea.2010.09.006

Abstract

The effect of thermal cycling on the load-controlled tension-tension fatigue behavior of a Ni-Ti-Fe shape memory alloy (SMA) at room temperature was studied. Considerable strain accumulation was observed to occur in this alloy under both quasi-static and cyclic loading conditions. Though, in all cases, steady-state is reached within the first 50-100 cycles, the accumulated steady-state strain, εp,ss, is much smaller in thermally cycled alloy. As a result, the fatigue performance of them was found to be significantly enhanced vis-a-vis the as-solutionized alloy. Furthermore, under load-controlled conditions, the fatigue life of Ni-Ti-Fe alloys was found to be exclusively dependent on εp,ss. Observations made by profilometry and differential scanning calorimetry (DSC) indicate that the 200-500% enhancement in fatigue life of thermally cycled alloy is due to the homogeneous distribution of the accumulated fatigue strain.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Shape Memory Alloy; Fatigue; Martensitic Phase Transformation; Plastic Deformation; Thermal Cycling
ID Code:62545
Deposited On:22 Sep 2011 03:16
Last Modified:22 Sep 2011 03:16

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