Combinational rate effects on the performance of nano-grained pseudoelastic Nitinols

• This letter completes the previous published letter in ‘Materials Letters’ (DOI:10.1016/j.matlet.2010.10.026).
• This study elucidates the nature of thermomechanical SMAs' behaviors during complex compressive loading-unloading rates with the presence of solid-state phase transition.
• The findings are first-time reported work and they can be generalized for other thermomechanical smart materials.

Combinational loading-unloading rate effects were studied on the behavior of NiTi shape memory alloys (SMAs) under nanoindentation loads. While combinational loading rates showed negligible effects on the performance of NiTi SMAs, the combinational unloading rates did show significant effects on hysteresis energy. The heating-cooling phenomenon during the loading stage and the sole cooling during the unloading stage explain the effects. This study elucidates the nature of thermomechanical SMAs' behaviors during complex compressive loadings with the presence of solid-state phase transition.