Crystallography and morphology of antiphase boundary-like structure induced by martensitic transformation in Ti–Pd–Fe alloy

• The APB-like structure are observed in both 9R and B19 martensite of Ti–Pd–Fe alloy.
• Atomic displacement on APB-like structure reflects the microdomain by pre-martensite.
• The density of APB-like contrasts are affected by Fe content in Ti–Pd–Fe alloy.

The antiphase boundary (APB)-like structure of both 9R and B19 martensites in the Ti–Pd–Fe alloy was investigated by means of transmission electron microscopy. Some APB-like structures with curved and wide contrasts along the (0 0 1)9R basal plane are observed in 9R martensitic plates. The atomic displacement on the APB-like structure reflects the atomic movement stemming from the microdomains formed as a pre-martensitic transformation. The displacement vector of the APB-like structure in the B19 martensite can be expressed as R = 〈1/3 0 −1/2〉B19. The density of APB-like contrasts increases by the substitution of Fe for Pd in Ti–Pd–Fe alloy.