Combining indentation and diffusion couple techniques for combinatorial discovery of high temperature shape memory alloys

Shastry, VV and Divya, VD and Azeem, MA and Paul, A and Dye, D and Ramamurty, U (2013) Combining indentation and diffusion couple techniques for combinatorial discovery of high temperature shape memory alloys. In: Acta Materialia, 61 (15). pp. 5735-5742.

PDF Act_Mate_61-15_5735_2013.pdf - Published Version Restricted to Registered users only Download (1MB) | Request a copy

Abstract

We demonstrate the possibility of accelerated identification of potential compositions for high-temperature shape memory alloys (SMAs) through a combinatorial material synthesis and analysis approach, wherein we employ the combination of diffusion couple and indentation techniques. The former was utilized to generate smooth and compositionally graded inter-diffusion zones (IDZs) in the Ni-Ti-Pd ternary alloy system of varying IDZ thickness, depending on the annealing time at high temperature. The IDZs thus produced were then impressed with an indenter with a spherical tip so as to inscribe a predetermined indentation strain. Subsequent annealing of the indented samples at various elevated temperatures, T-a, ranging between 150 and 550 degrees C allows for partial to full relaxation of the strain imposed due to the shape memory effect. If T-a is above the austenite finish temperature, A(f), the relaxation will be complete. By measuring the depth recovery, which serves as a proxy for the shape recovery characteristic of the SMA, a three-dimensional map in the recovery temperature composition space is constructed. A comparison of the published Af data for different compositions with the Ta data shows good agreement when the depth recovery is between 70% and 80%, indicating that the methodology proposed in this paper can be utilized for the identification of promising compositions. Advantages and further possibilities of this methodology are discussed.

Item Type:	Journal Article
Publication:	Acta Materialia
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Shape Memory Alloys; High Temperature; Indentation; Austenite to Martensite Phase Transformation; Combinatorial Methods
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	10 Oct 2013 05:23
Last Modified:	10 Oct 2013 05:23
URI:	http://eprints.iisc.ac.in/id/eprint/47477

Actions (login required)

View Item