Abstract
The Ti17(α+β)-Ti17(β)dual alloy-dual property blisk produced using Linear Friction Welding(LFW)is considered as high-performance component in advanced aeroengine.However,up to now,microstructure evolution and relationship between microstructure and micro mechanical properties of LFWed Ti17(α+β)/Ti17(β)dissimilar joint have not been thoroughly revealed.In this work,complex analyses of the phase transformation mechanisms of the joint are conducted,and phase transformations in individual zones are correlated to their microhardness and nanohard-ness.Results reveal that α dissolution occurs under high temperatures encountered during LFW,which reduces microhardness of the joint to that of Ti17(α+β)and Ti17(β).In Thermo-Mechanically Affected Zone of Ti17(α+β)(TMAZ-(α+β))side joint,a large number of nanocrystalline α phases form with different orientations.This microstructure strengthens signifi-cantly by fine grains which balances partial softening effect of α dissolution,and increases nanohardness of α phase and microhardness of TMAZ-(α+β).Superlattice metastable β phase precipitates from metastable β in Weld Zone(WZ)during quick cooling following welding,because of short-range diffusion migration of solute atoms,especially β stabilizing elements Mo and Cr.The precipitation of the superlattice metastable β phase results in precipitation strengthening,which in turn increases nanohardness of metastable β and microhardness in WZ.
基金项目
National Science and Technology Major Project,China(2017-Ⅶ-0005-0098)
National Natural Science Foundation of China(52105400)
State Key Laboratory of Solidification Processing,China(2021-TS-07)
Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(CX2023008)
NETL
NSTL
万方数据