Microstructural evolution and dynamic recrystallization mechanisms of additively manufactured TiAl alloy with heterogeneous micro structure during hot compression
Microstructural evolution and dynamic recrystallization mechanisms of additively manufactured TiAl alloy with heterogeneous micro structure during hot compression
Microstructural evolution and dynamic recrystallization(DRX)mechanisms of a Ti-48Al-2Cr-2Nb(at.％)alloy prepared by selective electron beam melting(SEBM)during hot deformation at 1150 ℃ and 0.1 s-1 were investigated by hot compression tests,optical microscope(OM),scanning electron microscope(SEM),electron back-scattered diffraction(EBSD)and transmission electron microscope(TEM).The results show that the initial microstructure of the as-SEBMed alloy exhibits layers of coarse y grains and fine γ+α2+(α2/γ)lamellar mixture grains alternately along the building direction.During the early stage of hot deformation,deformation twins tend to form within the coarse grains,facilitating subsequent deformation,and a small number of DRX grains appear in the fine-grained regions.With the increase of strain,extensive DRX grains are formed through different DRX mechanisms in both coarse and fine-grained regions,involving discontinuous dynamic recrystallization mechanism(DDRX)in the fine-grained regions and a coexistence of DDRX and continuous dynamic recrystallization(CDRX)in the coarse-grained regions.
关键词
TiAl合金/电子束选区熔化/异构组织/不连续动态再结晶/连续动态再结晶
Key words
TiAl alloy/selective electron beam melting/heterogeneous microstructure/discontinuous dynamic recrystallization(DDRX)/continuous dynamic recrystallization(CDRX)
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基金项目
Shaanxi Province Key Research and Development Projects,China(2023KXJ-071)
National Natural Science Foundation of China(52274402)
National Natural Science Foundation of China(52174381)
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