A guide to shape memory and superelasticity in Nitinol medical devices

Abstract

Shape memory and superelasticity properties of Nitinol have allowed the development of many novel medical devices. The intent of this paper is to approach the shape memory effect from the perspective of the attributes of a simple, yet elegant Nitinol device, the Homer Mammaloktrade mark needle localizer. Manufacturing methods, deformation behavior and temperature dependence of the device will be briefly reviewed.

Experimental Evaluation on the Influence of Autoclave Sterilization on the Cyclic Fatigue of New Nickel-Titanium Rotary Instruments

“…Heat treatments of the alloy can influence the transitional temperature at which a transformation between austenite and martensite takes place (35).…”

Fatigue of Nitinol: The state-of-the-art and ongoing challenges

“…For temperatures above the austenite finish temperature, and in strain-based fatigue analysis, the greater temperature may result in lower fatigue limits (Pelton et al, 2013). The difference between the test temperature and the austenite finish temperature of the Nitinol has been reported to be a more important factor than the absolute test temperature (Pelton et al, 2004). Pelton et al (Pelton et al, 2013) investigated the effect of relative test temperatures, ∆T, which is the difference between test temperature and the austenite finish temperature, of medical grade Nitinol (Ni 50.8 Ti 49.2 ) for a 10 7 cycles run-out.…”

Large Deformation of Nitinol Under Shear Dominant Loading

“…The effect of large sheardominated deformation in SMAs and the resulting phase transformation and plasticity is relevant in many of these applications, including ductile fracture, the micromechanics of void growth and coalescence, embedded SMAs, and numerous biomedical applications including stents, venacava filters, braided catheters, surgical tools and others (see for example [4] and the references therein). However, it is remarkably difficult to achieve a state of pure shear in most specimen geometries.…”