In situ straining investigation of slip transfer across α₂ lamellae at room temperature in a lamellar TiAl alloy

Abstract

Processes by which deformation spreads throughout a lamellar TiAl alloy have been investigated by in situ tensile experiments performed at room temperature in a transmission electron microscope. Several situations are found and analysed in which dislocations cross the γ/α₂ interfaces and the α₂ lamellae – the hard phase of the structure. Conditions by which strain transfer can be elastically mediated across sufficiently thin α₂ lamellae are discussed.

Acknowledgements

The authors acknowledge the Indo-French Centre for the Promotion of Advanced Research, New Delhi for sponsoring this project (No. 2308-2) and for funding the visit of one of the authors (JBS) to CEMES Toulouse, France. The authors are also grateful to J. Crestou of CEMES for his help in preparation of the thin foil.

Notes

†Reflecting the tetragonal symmetry of TiAl, the ⟨hkl] notation allows every permutation between h and k while ±l is ascribed to the third position 1.