Depth Profile of Titanium Alloy (Ti-6Al-4V) and Residual Stress Measured by Using X-Ray Diffraction after Metal Cutting Assisted by High-Pressured Jet Cooling Evaluation of Etching Methods: ION Beam (EDOS) and Electro-Chemical Etching

Titanium alloys are used in aerospace industry owing to their high strength to weight ratio. These alloys are considered to be difficult to machine due to their rigidity and poor thermal conductivity. High-pressure jet-assisted machining of titanium alloys is beneficial. It not only increases production efficiency, by increasing the cutting speed and lowering temperature both in cutting zone and the cutting tool, but also improves chip control, and increases tool life. It also produces better surface integrity and compress residual stress, which improves the properties of work metals such as fatigue. In order to compare the effect of high-pressure jet-assisted machining on the work pieces of Ti-6Al-4V alloy, the depth profile of residual stress was measured using xray diffraction. As comparison, the depth profile of residual stress was also measured for the conventional machined work pieces. It was found that the residual stress was a function of machining parameters, such as cutting speed, feeding force and depth of cut and particularly the high-pressure jet increases the amount of residual compressional stresses in both cutting and feed direction. In the present paper, Ti6A14V rod was machined by turning in two different manners, finishing and roughing. Tests were conducted on a lathe using different cooling systems, high pressure and conventional. To illustrate the effect of high-pressure jet assisted machining on the properties of the work piece of Ti-6-Al-4V and the depth profile of its residual stress, X -ray defractometer was used. The maximal amplitude of residual stress, at both the longitude (feeding direction) and transversal (cutting) directions, the depth of compress residual stress and the depth of the total residual stress will be present as the function of the machining parameters.