Zhang Tiangang, Sun Ronglu, Zhang Hongwei, et al. Segregation Behavior ofβ-phase in TC4 Laser Cladding Layer on Ti811 Alloy[J]. Special Casting & Nonferrous Alloys, 2018,38(1):5-9.
The TC4 laser cladding layer was prepared on the surface of Ti811 alloys with coaxial powder feeding.The microstructure andβ-phase segregation of the coating were analyzed by using X-ray diffraction(XRD)
scanning electron microscope(SEM)and energy dispersive spectrometer(EDS).The results reveal that
the typicalβ-phase segregation occurs in the cladding layer and appears as the large dark area.The microstructure of the non-β-phase segregation region of the cladding layer shows a typical widmanstatten structure.Many accicular martensiticα′-Ti and trace residualβ-Ti are distributed in the grain boundaries ofα-Ti
and nano particles ofα2 phase are dispersed in the cladding layer.In theβ-phase segregation region of the coating
a large area of residualβ-Ti appears in the microstructure while the grain boundaries ofα-Ti and accicular martensiticα′-Ti are obviously reduced
which are attributed to the molten pool formed by laser cladding cooling in a vary fast way and leaving no time for the phase transition of originalβgrains.