Microstructure and failure mechanism in As-deposited, vacuum plasma-sprayed Ti-6Al-4V alloy

摘要: The microstructure, phase composition, and chemical composition of vacuum plasma-sprayed Ti-6Al-4V alloys were examined in detail using a variety techniques, including x-ray diffraction, photoelectron spectroscopy, transmission electron microscopy. observed chemistry structure related to the conditions under which deposit was formed equilibria Ti alloy system. porosity range 3 5%. A slight decrease Al content increase amount oxygen hydrogen found relative starting powder. Within individual splats, columnar solidification can be seen. However, as-deposited material is ≥90% α′ martensite that present form fine lathes on order 500 nm width surrounded by residual β-phase. This herringbone obscures some extent preexisting as-solidified fails at low elongations (∼1%) when tested tension, with macroscopic stress-strain curve, appears quite brittle. Examination fracture surface, however, reveals ductile failure mode within consistent described above. Sections perpendicular surface show occurs weak splat boundaries through development growth voids between splats.