Related Experiment Video
Updated: Aug 6, 2026

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Elinvar Effect by Nanoscale Displacive Phase Transformation in Martensites
Die Liu1, Yao Liu1, Junming Gou1
1Xi'an Jiaotong University, Frontier Institute of Science and Technology, and State Key Laboratory for Mechanical Behavior of Materials, Xi'an 710049, China.
None:
Ferroelastic alloys suffer modulus softening prior to the martensitic transformation, but still exhibit normal cooling-hardening effect below the martensitic transformation finish temperature, M_{f}. Here we report an unprecedented phenomenon that a martensitic state can show nearly temperature-independent modulus (i.e., Elinvar effect) below M_{f}, as exhibited in Ni-Fe-Mn-Ti alloys. The Elinvar martensites have a hierarchical domain structure, where two types of orthorhombic nanomartensites with distinct atomic modulation periods and magnetic states coexist within an individual ferroelastic domain. Their small free-energy difference gives rise to a nanoscale displacive phase transformation from one to another, and the moderate modulus softening compensates for the ever-present elastic hardening, leading to the wide temperature range Elinvar effect. This finding is a new insight of martensitic phase transformation, which might help to discover technically desired properties, such as the temperature-independent modulus and good ductility at cryogenic temperatures.
Related Concept Videos
Ferromagnetism
Phase Transitions: Melting and Freezing
π Electron Effects on Chemical Shift: Overview
Imperfections in Crystal Structure: Non-Stoichiometric Defects

