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Electrolytic phase extraction: a useful technique to evaluate precipitates in nitinol

Published online by Cambridge University Press:  15 June 2012

Roy G. Baggerly
Roy G. Baggerly*
Affiliation:
Boeing Research and Technology, Northwest Analytical Laboratories, Seattle, Washington 98124
*
a)Electronic mail: roy.g.baggerly@boeing.com
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Abstract

Nitinol is a shape memory alloy based on the inter-atomic compound having a composition of 50  at% each of Ni and Ti, NiTi. The shape memory effect results from a reversible martensitic phase transformation. An increasing solubility range with temperature on the Ni-rich side can produce a precipitation reaction resulting in a slight matrix composition adjustment with appropriate heat treatment. Electrolytic phase extraction (Andrews and Hughes, 1957) is used to evaluate the secondary phases in the alloy and Ti2Ni and TiC are positively identified using powder wide-angle X-ray diffraction procedures. Two samples of an Ni-rich alloy at 57 and 60 at% are also analyzed. These Ni-rich samples show Ti2Ni and an additional phase, Ni3Ti.

Keywords

X-ray diffractionnitinolelectrolytic phase extraction
Type
Technical Articles
Information
Powder Diffraction , Volume 27 , Issue 2 , June 2012 , pp. 136 - 139
Copyright
Copyright © International Centre for Diffraction Data 2012

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References

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