Lamellar globularization in the dual-phase titanium alloy is the key to improving plasticity and strength.However,the mechanism has not been fully elucidated so far.In this work,the role of phase/grain bound-ary in th...Lamellar globularization in the dual-phase titanium alloy is the key to improving plasticity and strength.However,the mechanism has not been fully elucidated so far.In this work,the role of phase/grain bound-ary in the static globularization of TC17 alloy was systematically studied by setting differentαphase con-tent before annealing through low-and high-temperature deformation.Isothermal compression causes the parallel distribution and fragmentation of 3Dαplates and few globularαparticles are formed at a strain rate of 1 s^(-1).Post-deformation annealing promotes the static globularization ofαphase while it is affected by initialαphase content.After 730°C deformation,the development ofα/αinterface by absorbing dislocations promotes the formation of globularαgrains based on the nucleation of sepa-ratedαparticles and pre-recoveryαsubgrain during subsequent annealing.Theα/α/βandα/β/βtriple junctions formed due to highαcontent with about 36%volume fraction are favorable for the further nucleation and growth of globularαgrains by reducing interface energy,forming a 3D irregularαplate.Then nucleation and growth of theβphase dominate the microstructure evolution during subsequent an-nealing,resulting in the local dissolution of the plate and formation ofαrods.After 850°C deformation,theαphase tends to nucleate at theβ/β/βtriple junctions and grow into a lamellar shape along the high energyβ/βgrain boundary due to lowαcontent with about 7%volume fraction.Theαnucleation that maintains the Burgers orientation relationship(BOR)with the surroundingβphase grows along the habit plane and thickens slowly,resulting in the formation of a precipitatedαplate with a flat surface and the suppression of static globularization.The comprehensive investigation of lamellar globularization provides guidance for optimizing the 3D microstructure and properties of dual-phase titanium alloy.展开更多
基金the financial support from the National Key R&D Program of China(Grant No.2022YFB3707201)the Science Fund for Distinguished Young Scholars from Shaanxi Province(No.2020JC-17)+2 种基金NPU AoXiang Distinguished Young Schol-ars(Grant Nos.0604022GH0202143,0604022SH0201143)the Funding of Young Top-notch Talent of the National Ten Thousand Talent Program,the Fundamental Research Funds for the Central Universities(No.3102022gxb004)Science Center for Gas Tur-bine Project(No.P2022-A-IV-001-002)。
文摘Lamellar globularization in the dual-phase titanium alloy is the key to improving plasticity and strength.However,the mechanism has not been fully elucidated so far.In this work,the role of phase/grain bound-ary in the static globularization of TC17 alloy was systematically studied by setting differentαphase con-tent before annealing through low-and high-temperature deformation.Isothermal compression causes the parallel distribution and fragmentation of 3Dαplates and few globularαparticles are formed at a strain rate of 1 s^(-1).Post-deformation annealing promotes the static globularization ofαphase while it is affected by initialαphase content.After 730°C deformation,the development ofα/αinterface by absorbing dislocations promotes the formation of globularαgrains based on the nucleation of sepa-ratedαparticles and pre-recoveryαsubgrain during subsequent annealing.Theα/α/βandα/β/βtriple junctions formed due to highαcontent with about 36%volume fraction are favorable for the further nucleation and growth of globularαgrains by reducing interface energy,forming a 3D irregularαplate.Then nucleation and growth of theβphase dominate the microstructure evolution during subsequent an-nealing,resulting in the local dissolution of the plate and formation ofαrods.After 850°C deformation,theαphase tends to nucleate at theβ/β/βtriple junctions and grow into a lamellar shape along the high energyβ/βgrain boundary due to lowαcontent with about 7%volume fraction.Theαnucleation that maintains the Burgers orientation relationship(BOR)with the surroundingβphase grows along the habit plane and thickens slowly,resulting in the formation of a precipitatedαplate with a flat surface and the suppression of static globularization.The comprehensive investigation of lamellar globularization provides guidance for optimizing the 3D microstructure and properties of dual-phase titanium alloy.
