The effect of microstructure on the erosion of Ti-6Al-4V by spherical particles at 90° impact angles

Ti-6A1-4V alloy in two microstructural forms, equiaxed α + β and a basketweave α + β structure, was eroded. The erosion conditions utilized were an impact angle of 90°, spherical silica particles 210 μm in diameter and a velocity of 61 m s-1. Examination of the eroded surfaces indicated that both microstructures were extensively covered by a layer of glass approximately 2 μm thick prior to the onset of steady state erosion. Thermal softening and plastic flow of erodent on impact formed the glass layer. In this way a large area of the target was protected from direct impact. Consequently little evidence of subsurface damage during erosion was found for either structure. Material loss during steady state erosion was possible only at discontinuities in the glass layer or when it was removed to reveal a fresh metallic surface. The primary mechanism of metal removal was found to be the same in incubation and steady state irrespective of the microstructure. Small platelets were formed from overlapping strain fields by several individual impacts. Other operating mechanisms were cutting due to fractured or preexisting irregular erodent and removal of lips from oblique impacts. © 1984