The ordering and antiphase boundary-like fault found in the α”-martensite of β-Ti shape memory alloys were studied. Long-range chemical ordering was not found, but antiphase boundary-like faults were observed in every martensite plate studied by transmission electron microscopy. These faults have morphology similar to the antiphase boundaries observed in ordered phases. The superlattice reflections observed in some previous works were a consequence of multiple diffractions. antiphase boundary-like faults were not observed in the parent phase, leading to the conclusion that the faults were introduced by the martensite transformation. The fault took the form of a wavy tube running perpendicular to the habit plane. The fault was a so-called transformation-induced antiphase boundary with an additional small displacement due to the pre-existing athermal ω phase. The displacement vector was determined to be [-3/50, -23/50, 1/2]. Geometrical aspects of the formation of antiphase boundary-like faults were also considered.

Antiphase Boundary-Like Stacking Fault in α''-Martensite of Disordered Crystal Structure in β-Titanium Shape Memory Alloy. T.Inamura, H.Hosoda, H.Y.Kim, S.Miyazaki: Philosophical Magazine, 2010, 90[25], 3475-98