In the present work

we have extensively examined the alternative-band microstructure of a Ti-47Al-2Cr-2Nb alloy fabricated via direct laser deposition by means of high resolution transmission electron microscopy and selected area electron diffraction. The studied samples exhibit two types of long-periodic stacking ordered phase with 6H and 18R structures

which were never reported for those obtained by traditional approaches. Moreover

the ordered phases possess stacking sequences of ABCBACA and ABCABCBCABCACABCABA

being analogous to the periodically arranged stacking faults in α

2

and γ phases

respectively. With the presence of these unusual structures

the as-deposited sample tends to have superior mechanical properties.

IMPACT STATEMENT

Unusual ordered phases with long periodic stacking structures

seldom reported in the TiAl alloys obtained by traditional approaches

were comprehensively characterized

and demonstrated to possess excellent mechanical properties.