摘要
Theα/βinterface is central to the microstructure and mechanical properties of titanium alloys.We investigate the structure,thermodynamics and migration of the coherent and semicoherent Tiα/βinterfaces as a function of temperature and misfit strain via molecular dynamics(MD)simulations,thermodynamic integration and an accurate,DFT-trained Deep Potential.The structure of an equilibrium semicoherent interface consists of an array of steps,an array of misfit dislocations,and coherent terraces.Analysis determines the dislocation and step(disconnection)array structure and habit plane.The MD simulations show the detailed interface morphology dictated by intersecting disconnection arrays.The steps are shown to facilitateα/βinterface migration,while the misfit dislocations lead to interface drag;the drag mechanism is different depending on the direction of interface migration.These results are used to predict the nature ofαphase nucleation on cooling through theα-βphase transition.
基金
S.W.and D.J.S.gratefully acknowledges the support of the Hong Kong Research Grants Council Collaborative Research Fund C1005-19G
J.H.acknowledges support of the Early Career Scheme(ECS)grant from the Research Grants Council of Hong Kong SAR,China[Project No.CityU21213921]
Donation for Research Projects 9229061.
