On the plasticity of small-scale nickel-titanium shape memory alloys

Focused ion beam machined compression pillars created from [1 1 1], [0 0 1] and [2 1 0] NiTi demonstrate that orientation plays a dominant role in determining dislocation flow stress in stress-induced martensite. This is in contrast to bulk NiTi in which martensite strength is primarily dictated by precipitate size. Post-mortem transmission electron microscopy and Laue microdiffraction measurements reveal respectively dense dislocation structures and stabilized martensite consistent with bulk observations in heavily deformed NiTi.