Helium Nanobubbles Enhance Superelasticity and Retard Shear Localization in Small-Volume Shape Memory Alloy

摘要: The intriguing phenomenon of metal superelasticity relies on stress-induced martensitic transformation (SIMT), which is well-known to be governed by developing cooperative strain accommodation at multiple length scales. It therefore scientifically interesting see what happens when this natural scale hierarchy disrupted. One method producing pillars that confine the sample volume micrometer scale. Here we apply yet another intervention, helium nanobubbles injection, produces porosity order several nanometers. While pillar confinement suppresses superelasticity, found dispersion 5–10 nm do opposite promoting in a Ni53.5Fe19.5Ga27 shape memory alloy. role modulating competition between ordinary dislocation slip plasticity and SIMT discussed.