Evolution and stability of phases in a high temperature shape memory alloy Ni49.4Ti38.6Hf12

Suresh, KS and Kim, DongIk and Bhaumik, SK and Suwas, Satyam (2014) Evolution and stability of phases in a high temperature shape memory alloy Ni49.4Ti38.6Hf12. In: INTERMETALLICS, 44 . pp. 18-25.

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Abstract

Ni49.4Ti38.6Hf12 shape memory alloy has been characterized for structure, microstructure and transformation temperatures. The microstructure of the as-cast sample consists of B19' and R-phases, and (Ti,Hf)(2)Ni precipitate phase along the grain boundaries in the form of dendrites. The microstructure of the solution treated sample contains only B19' martensite phase, whereas a second heat treatment after solutionizing results in reappearance of the R-phase and the (Ti,Hf)(2)Ni grain boundary precipitate phase in the microstructure. A detailed microstructural examination shows the presence of precipitates having both coherent and incoherent interface with the matrix, the type of interface being dictated by the crystallographic orientation of the matrix phase. The present study shows that the (Ti,Hf)(2)Ni precipitates having coherent interface with the matrix, drive the formation of the R-phase in the microstructure. (C) 2013 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	INTERMETALLICS
Publisher:	ELSEVIER SCI LTD
Additional Information:	copyright for this article belongs to ELSEVIER SCI LTD,ENGLAND
Keywords:	Intermetallics, miscellaneous; Shape-memory effects; Martensitic transformations; Microstructure; Phase interfaces; Electron microscopy, scanning
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	17 Dec 2013 10:08
Last Modified:	17 Dec 2013 10:08
URI:	http://eprints.iisc.ac.in/id/eprint/47932

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