In-situ observation of nucleation, growth and interaction of deformation-induced <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"><mml:mrow><mml:msup><mml:mi mathvariant="bold">?</mml:mi><mml:mo>?</mml:mo></mml:msup></mml:mrow></mml:math> martensite in metastable Ti–10V–2Fe–3Al

Microstructure evolution, dominated by the formation of deformation-induced ?? martensite during 3-point bending a metastable ? Ti–10V–2Fe–3Al alloy containing 5% ?, was observed in-situ using forward-scatter electron imaging and backscattering diffraction. plates nucleated heterogeneously from {580}?? habit planes at ?-? interfaces triggered nucleation additional advancing interface growth upon impingement with high-angle boundaries. Further thickening impinged led to build-up strain energy which induced 13031?0?'' twinning within obstacle-forming plates. Until now, this system in Nb Ta alloyed Ti shape memory alloys only. This study is also first document activation matrix. The forming variants were {011}?? compound twin-related variant pairs, each up two individual planes. These pairs consistently predicted determining grain-average stress finite element analysis computing available work transformation variants. At higher indenter loads, grains that unfavourably oriented accommodated local aggregates different variants, obeying either {111}?? type I or 211?'' II twin relationships. Scanning transmission microscopy revealed substructures comprising columnar domains perpendicular plane along absence lattice invariant deformation. involved ledge ??-? interfaces.