Manipulating Phase Coexistence to Tune Non-Hysteretic Superelasticity in a Metal

August 31, 2020
Manipulating Phase Coexistence to Tune Non-Hysteretic Superelasticity in a Metal
(Left) One-dimensional cuts through diffuse neutron scattering showing the emergence of short-range ordering peaks as a function of annealing temperature. (Right) Scattering in the HHL plane annealed at 298 K (top) and 633 K (bottom). The red box shows the region of the cuts plotted at left. At high temperatures ordered and disordered crystal structures coexist.

Scientific Achievement

NiCoFeGa alloy single crystals are seen to exhibit non-hysteretic superelasticity that can be tuned by manipulating the crystal microstructure via controlled annealing.

Significance and Impact

The possibility of tunable and non-hysteretic superelasticity over a wide temperature range paves the way for a new class of functional materials with a broad range of applications.

Research Details

  • X-ray diffraction tracks lattice parameters as function of strain and shows how the superelasticity is connected to the crystal structure. 
  • Neutron scattering reveals a temperature dependent microstructure consisting of crystalline ordered and disordered regions, and its dependence on annealing temperature.
  • Samples were further characterized by electron microscopy.

“Unprecedented non-hysteretic superelasticity of [001]-oriented NiCoFeGa single crystals”
Haiyang Chen, Yan-Dong Wang, Zhihua Nie, Runguang Li, Daoyong Cong, Wenjun Liu, Feng Ye, Yuzi Liu, Peiyu Cao, Fuyang Tian, Xi Shen, Richeng Yu, Levente Vitos, Minghe Zhang,  Shilei Li, Xiaoyi Zhang, Hong Zheng, J. F. Mitchell and Yang Ren,
Nature Materials, (2020). 
DOI: https://doi.org/10.1038/s41563-020-0645-4