An in situ neutron diffraction study of anomalous superelasticity in a strain glass Ni ₄₃ Fe ₁₈ Ga ₂₇ Co ₁₂ alloy

Journal Article · Sat Jul 18 00:00:00 EDT 2015 · Journal of Applied Crystallography (Online)

DOI:https://doi.org/10.1107/S1600576715011334· OSTI ID:1326097

Zhang, Q. H.; Zhai, Z.; Nie, Z. H.; Harjo, S.; Cong, D. Y.; Wang, M. G.; Li, J.; Wang, Y. D.

Superelastic behavior is traditionally related to the martensitic transition with a collective transformation scenario in some shape memory alloys. A kind of quasi-linear superelasticity accompanied by a finite avalanche or confined martensitic transformation was recently found in some alloy systems with strain glass state. Here, anin situneutron diffraction technique was used to study the deformation behavior in an Ni₄₃Fe₁₈Ga₂₇Co₁₂alloy with strain glass state in order to reveal the new intrinsic physical nature of the quasi-linear superelasticity. A significant modulus softening prior to the stress-induced martensitic transformation was observed during compression in the studied alloy, which is similar to the characteristics exhibited in the tweed precursor phenomena prior to temperature-induced martensitic transformation. Moreover, the diffraction peak broadening was further shown during the elastic stage of deformation for both single-crystal and polycrystalline samples, which mainly stems from the short-range fluctuation in the strain field inside each grain based on Williamson–Hall analysis. The authors believe that there exists a spatial heterogeneity in the modulus of the confined martensitic transformation alloy.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: FOREIGN
• OSTI ID: 1326097
• Journal Information: Journal of Applied Crystallography (Online), Vol. 48, Issue 4; ISSN 1600-5767
• Publisher: International Union of Crystallography
• Country of Publication: United States
• Language: ENGLISH