Dongyi Seo

Interfacial strengthening of β phase in a fully lamellar structure of TiAl alloy containing W

The strengthening of the β phase in two fully lamellar structures with different lamellar spacing of a Ti–48 at.% Al–2 W at.% alloy during creep deformation has been investigated. It was found that the β phase precipitates during aging treatments only within regions of α2 lamellae following their dissolution. The strengthening of the β phase is more effective in the coarser lamellar structure, because the wider β precipitation zones, which replace the prior coarser α2 lamellae, hinders dislocation motion stronger than the narrower ones.

An analysis of growth direction of β phase precipitates in a TiAlW alloy

beta phase precipitates at the lamellar interface after aging heat treatment in a TiAlW alloy. The orientation relationship (OR) between the beta and gamma phase is (gamma)// (beta), (111)(gamma)//(110)(beta). Six different beta phase variants can be observed along the [111](gamma) zone axis. The OR between beta and gamma phase and the growth directions of beta precipitates are predicted from the invariant line strain model