中温应力作用下Ti-42Al-6.5V-2Zr合金淬火马氏体的演变机制OA

TiAl alloys demonstrate significant application potential in the aerospace field because of their low density,high specific stiffness and strength,and excellent high-temperature mechanical properties.However,challenges such as poor room-temperature plasticity,limited damage tolerance,and difficulties in hot working still hinder their widespread use in practical engineering.Research has suggested that obtaining a uniform and fine lamellar microstructure through microstructural control is an effective approach for enhancing room-temperature plasticity and improving workability.This study focused on a Ti-42Al-6.5V-2Zr alloy,which was subjected to quenching from the β single-phase region to obtain a microstructure dominated by lath martensite α2.Subsequent holding and loading experiments were performed on the martensitic structure to achieve microstructural refinement of the TiAl alloy.The subsequent microstructural evolution during intermediate-temperature holding and loading was studied by high-energy X-ray diffraction.The applied stress significantly promotes the phase transformation from α2 to γ.The mechanical anisotropy between the α2 and γ phases leads to rapid accumulation of elastic strain energy and crystal defects within the α2 phase,which markedly accelerates the formation of the lamellar γ phase.