In-situ nanoindentation study of phase transformation in magnetic shape memory alloys

April 18, 2014 by Hemali Tanna

Texas A&M University researchers led by Dr. Xinghang Zhang in the Department of Mechanical Engineering have examined stress induced martensitic phase transformations in magnetic shape memory alloys via in-situ nanoindentation technique.

The paper titled "Two Types of Martensitic Phase Transformations in Magnetic Shape Memory Alloys by in-situ Nanoindentation Studies" was published in the March 31 issue (2014) of Advanced Materials. The first author of the paper is Mr. Yue Liu, a Ph.D. candidate in Dr. Zhang's research group.

Ni based magnetic alloys (MSMAs) have broad applications for actuators and microelectromechanical systems (MEMS) devices. Two-stage stress induced martensitic phase transformation, a widely observed phenomenon in these alloys, is described conventionally as a first stage L21 (austenite)-to-10M/14M (M: modulated martensite) transition, followed by a second stage 14M-to-L10 (tetragonal martensite) transformation at higher stresses.

During their in-situ nanoindentation experiments on Ni54Fe19Ga27 in a transmission electron microscope, Zhang and his graduate student, Mr. Yue Liu, discovered two distinctive types of martensitic phase transformation: A reversible gradual L21-to-10M/14M phase transformation at low stress, and an irreversible abrupt transition from residual L21-to-L10 martensite at higher stress. This study provides new perspectives on understanding stress induced in MSMAs.

Explore further: New materials turn heat into electricity

More information: Liu, Y., Karaman, I., Wang, H. and Zhang, X. (2014), "Two Types of Martensitic Phase Transformations in Magnetic Shape Memory Alloys by In-Situ Nanoindentation Studies." Adv. Mater.. DOI: 10.1002/adma.201400217

Related Stories

New materials turn heat into electricity

November 7, 2011

Most of today's power plants--from some of the largest solar arrays to nuclear energy facilities--rely on the boiling and condensing of water to produce energy.

Can metals remember their shape at nanoscale, too?

November 8, 2011

University of Constance physicists Daniel Mutter and Peter Nielaba have visualized changes in shape memory materials down to the nanometric scale in an article about to be published in the European Physical Journal B.

Advances in glass alloys lead to strength, flexibility

March 4, 2014

( —What do some high-end golf clubs and your living room window have in common? The answer is glass, but in the golf clubs' case it's a specialized glass product, called metallic glass, with the ability to be bent ...

Recommended for you

Touchless displays superseding touchscreens?

October 2, 2015

While touchscreens are practical, touchless displays would be even more so. That's because, despite touchscreens having enabled the smartphone's advance into our lives and being essential for us to be able to use cash dispensers ...

Physicists map the strain in wonder material graphene

September 29, 2015

This week, an international group of scientists is reporting a breakthrough in the effort to characterize the properties of graphene noninvasively while acquiring information about its response to structural strain.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.