Plasticity and brittleness of the ordered βo phase in a TNM-TiAl alloy

In order to identify the reasons for brittleness of a TNM-TiAl alloy (Ti51.05Al43.9Nb4Mo0.95B0.1 in at.%), plastic deformation behaviour ordered βo phase is investigated. The corresponding powder was densified by Spark Plasma Sintering produce near lamellar microstructure made γ/α2 colonies surrounded γ and grains. Then, room temperature tensile studied carrying out tests additional in-situ straining experiments transmission electron microscope (TEM). TNM exhibits limited ductility, with fracture surface test specimens showing cleavage facets along interfaces. addition, grains contain nano-precipitates ωo deform plastically <111> superdislocations dissociated into two superpartial dislocations separated an antiphase boundary. These glide {011} planes are observed be localized pile-ups, which related strengthening precipitation within This localised hardening leads stress concentration grain boundaries assumed responsible delamination interfaces neighbouring colonies.