Abstract
Superelastic NiTi shape memory alloy (SMA) cuboidal micropillars (1μm × 1μm × 3μm) with average grain sizes (GS) of 26 nm, 127 nm and 421 nm are compressed by flat-tip nanoindentation. Increasing GS from 26 nm to 127 nm enhances the transformation by promoting nucleation and growth of martensite. Nevertheless, by further increasing GS to 421 nm, the overall transformation is significantly suppressed, leading to a non-monotonic variation in transformation stress, recoverable strain and hysteresis loop area with GS. Such strong effects of GS on microscale phase transformation behavior of SMA are quantitatively elucidated by a simple three-length-scale model in this paper.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
