The activation and the spreading of deformation in a fully lamellar Ti-47Al-1Cr-0.2Si Alloy

Jung Bahadur Singh (1) , Guy Molénat (2) , M. Sundararaman (1) , Srikumar Banerjee (1) , Georges Saada (3) , Patrick Veyssière (3) , Alain Couret (2)

1 Materials Science Division
2 CEMES - Centre d'élaboration de matériaux et d'études structurales
3 LEM - ONERA - CNRS - Laboratoire d'étude des microstructures [Châtillon]

The spreading of deformation in a lamellar Ti-47Al-1Cr-0.2Si alloy deformed under compression is studied at 25°C and 600 °C. This microstructure is largely dominated by twin related variants which are separated by either twin interfaces or thin α2 slabs. The alloy deforms at both temperatures by ordinary dislocations and twins. Deformation in a particular γ variant and its adjacent twin-related variant involves the same kind of glide system, either ordinary dislocations or twins. This property is found to be true for all twin related lamellae. The occurrence of this correlated glide is explained by the introduction of the notion of “pilot” and “driven” orientations. The lamellar orientation in which the operating glide system is activated on the basis of Schmid factor considerations is termed the pilot orientation. It imposes its deformation system on to the twin-related lamella, called the driven orientation whose deformation may not involve the slip system most favoured by the applied stress.

Mots clés: Physical Sciences

Jung Bahadur Singh, Guy Molénat, M. Sundararaman, Srikumar Banerjee, Georges Saada, et al.. The activation and the spreading of deformation in a fully lamellar Ti-47Al-1Cr-0.2Si Alloy. Philosophical Magazine, 2006, 86 (16), pp.2435-2456. ⟨10.1080/14786430600606826⟩. ⟨hal-00513666⟩