Direct physical evidence for the back-transformation of stress-induced martensite in the vicinity of cracks in pseudoelastic NiTi shape memory alloys

Gollerthan, S and Young, ML and Neuking, K and Ramamurty, U and Eggeler, G (2009) Direct physical evidence for the back-transformation of stress-induced martensite in the vicinity of cracks in pseudoelastic NiTi shape memory alloys. In: Acta Materialia, 57 (19). pp. 5892-5897.

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Abstract

Crack loading and crack extension in pseudoelastic binary NiTi shape memory alloy (SMA) miniature compact tension (CT) specimens with 50.7 at.% Ni (austenitic, pseudoelastic) was investigated using infrared (IR) thermography during in situ loading and unloading. IR thermographic measurements allow for the observation of heat effects associated with the stress-induced transformation of martensite from B2 to BIT during loading and the reverse transformation during unloading. The results are compared with optical images and discussed in terms of the crack growth mechanisms in pseudoelastic NiTi SMAs. Direct experimental evidence is presented which shows that crack growth occurs into a stress-induced martensitic microstructure, which immediately retransforms to austenite in the wake of the crack.

Item Type:	Journal Article
Publication:	Acta Materialia
Publisher:	Elsevier Science
Additional Information:	Copyright for this article belongs to Elsevier Science.
Keywords:	Shape memory alloys (SMA); Martensitic phase transformation; Infrared thermography; Fracture; Tension test
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	04 Dec 2009 05:28
Last Modified:	19 Sep 2010 05:53
URI:	http://eprints.iisc.ac.in/id/eprint/25070

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