Application of GOV (flow peening) process for Ti-6Al-4V of aerospace materials

From medical industry to aerospace applications, Titanium (Ti-6Al-4V) finds place because of its excellent mechanical features such as high temperature strength, corrosion resistance and poor thermal conductivity. Beside these superior properties it is known as difficult-to-cut material. Owing to this reason, non-traditional finishing and surface treatment methods namely abrasive flow machining (AFM) and shot peening are applied to obtain desired surface quality for Ti-6Al-4V. By bringing the advantages of surface quality and strength improvement of these two processes together, GOV (flow peening) process has been developed and patented. In this paper, the investigations of the effects of the GOV process parameters (number of cycles, steel ball size, media ratio) on the surfaces of the Ti-6Al-4V already pre-processed by electric discharge machining (EDM) are carried out. Surface roughness, Ra, material removal (MR) and white layer thickness are selected as performance parameters of in this study. Through the surface of Ti-6Al-4V, this prepared media is forced in two directions at high pressure. Surface improvement is performed by applying GOV process with a decrease of 1.37µm in the surface roughness value of Ra (from 2.17 µm to 0.80 µm) and decrease of white layer, weight of 4.4 mg which is supported by the SEM images. It is clear to understand that the white layer formed due to nature of EDM process is almost completely removed from the material surface. The GOV (flow peening) process can be used to improve surface quality without any excess chip removal.