Effects of Al concentration and resulting long-period superstructures on the plastic properties at room temperature of Al-rich TiAl single crystals

摘要: The role of Al5Ti3 and h-Al2Ti long-period superstructures on the plastic properties TiAl at room temperature is investigated five single crystals with aluminium content comprised between 54.7 at.%, 62.5 at.%. After annealing 1200°C for 1 h, superstructure develops in L10 (γ) matrix upon increasing Al concentration except Ti–62.5 at.%Al where substitutes Al5Ti3. CRSS for  <110]{111} first increases abruptly development Al5Ti3-type ordering. Then, reaches a plateau which dislocations assemble groups four to prevent extra anti-phase boundary (APB) from being engendered during glide throughout phase. In at.%Al, ordinary slip further precipitation phase, whereas it decreases when crystal fully transformed into single-phased <101] superlattice are primarily activated under both [210] [1 1 8.6] load orientations irrespectiv...