Quantitative analysis on the surface topography of Ti-6Al-4V machined by abrasive suspension jet

Surface topography is the intrinsic determinant of the roughness that is a significant evaluation standard for the machining quality of the abrasive suspension jet (ASJ). To achieve quantitative analysis on the surface topography machined by ASJ, this paper measured the roughness and the scratch size of the cutting surface with an ultra-deep three-dimensional microscope. Ti-6Al-4V (TC4), a typical hard machining material widely used in aviation industry, was chosen as the cutting target. From a macroperspective, the cutting surface is divided into four zones from top to bottom including the initial zone, the smooth zone, the transition zone, and the rough zone. With 1.6-μm set as the standard roughness, the length of the initial zones and the smooth zone were analyzed and determined. From a microperspective, there are a large number of particle scratches with micron scale size laid on the cutting surface. The experimental results showed that the length of the scratches in the initial zone was less than the one in the smooth zone, while it was opposite in the scratch depth and width, and that the initial zone is larger than the smooth zone in surface roughness could be explained. The abrasive particle size is the only influent parameters of the scratch size, and small abrasive particles can be used for reducing the roughness in the initial zone and smooth zone. The conclusions can provide theory guidance for abrasive water jet processing titanium alloys precisely.